Comment plus is a WordPress plugin that enriches the features of the standard comment system. It allows image attachment, notifications on new comments, welcome email on first comment posted and other powerful features like image watermarking, gallery of comments images and more.



Follow the steps below to install and activate Comment Plus in your blog.

      1. Open the ZIP archive you downloaded and find inside the documentation PDF (comment-plus.pdf) and the plugin archive (comment-plus-[ver].zip). [ver] is a three digits number (like 1.2.1) representing the version.
      2. Enter in your blog plugin panel and use the “Add New” action button (find it on top of the plugin list page)
      3. In the “Add Plugins” panel select the action button “Upload Plugin” on page top.
      4. A file selector will be shown and you can choose the ZIP package you extracted from the downloaded ZIP file.
      5. Please, DO NOT selected the downloaded package which contains the plugin and the documentation, but the ZIP archive inside that package.
      6. After the upload and the installation completed you can activate the plugin.


General settings

On general setting you should set the sender name and address of notifications. WordPress set them to your blog name and the email address if not specified.


Attaching images to comments

While leaving a comment the reader can attach a single image (JPG, GIF and PNG supported). The attached image will be inserted in the comment text following the layout settings on Comment Plus configuration panels (aligned top/bottom, left/center/right).
The inserted picture size is controlled by administrative settings (width, height and cropping). Generated thumbnails are saved in a cache and regenerated if you decide to change the size and cropping values.

Moderation of comments with images

It’s advisable to not publish immediately comments with an attachment, specially if your blog has readers in sensible categories (like children).
Comment Plus can be configured to keep every comment with an image on moderation status so you can check it before publishing it (and, maybe, sending a notification for new comments to all the subscribers).

Note: Comments are not changed at storage level, they are enriched with the attached image when displayed. Hence, if you disable the attachment feature, comments will be shown as usually.


It’s possible to select a PNG file to apply as watermark to each attached image. The PNG must be 512 x 512 px, almost all transparent and with your watermark white with 30% of opacity. These are only suggested values, feel free to experiment with different combinations. The watermark can be changed anytime, it will be reapplied to all images since the original ones are kept untouched. On images folder inside the plugin you can find a watermark picture example with a GIMP source file.
The watermark is applied centered on the picture, the basic idea is to avoid someone else to download readers provided images and reuse them elsewhere. Use as reference how the picture stock sites watermark their preview images. Here an example of a watermarked full size image. Original uploaded pictures are not watermarked, the watermark is applied on demand and the resulting image cached. To protect the folder containing the original pictures (wp-content/uploads/comment-plus) few files are added to that folder which locks the access on Apache and IIS servers. If you use nginx you should protect the folder adding rules to the nginx configuration.

Max picture size

Attached images could be too large and use to much disk space or bandwidth. Setting a max picture stored size, all the over-sized images are scaled down to fit inside a box of the specified dimension, without being distorted.


Notification of new comments

Readers can subscribe to be notified of new comments for any specific post. The subscription can be activated while leaving a new comment on that specific post. Subscription to new comments are based on the post. Subscribed readers will receive ALL new comments left on each post they’re subscribed to.

Notification limits

If a post receives a lot of comments, each subscriber receives a correspondent number of emails, and they could be too many. Comment Plus can suspend the notifications after a configurable number of notifications and then restore them if the subscriber “does something”, like come back to the post comments from a notification or after a specified number of days.


Notification of new replies

WordPress can allow comment threads, where a comment is left as reply to another comment. Readers can then subscribe only to single threads that are evolving instead to all the comments left on that post. It works like a forum discussion. The mechanic behind this second kind of subscription does not differ from the generic new comment notifications. See the replacement tags chapter to customize the messages.

Notification limits

Max notification limits do no apply to replies notification since they are really important to keep the discussion active and it is supposed that who activates them wants to receive every new comment added to the thread.


Welcome messages

Welcoming new readers when they leave a comment for the first time is not only kind but a way to engage them. The welcome email is sent only once at first comment and it is usually the best place to promote your blog, exposing main sections and topics, inviting the user to subscribe a newsletter or to explore your catalog.


Thankyou message

The thank you message is sent to the reader on his first comment left on a post. If the reader leaves two comments in two different posts he receive two thank you emails. This kind of message is used to stimulate the conversation, asking to visit again the post and check it for new comments. You should invite the reader to keep the email as reference for future access to the post and, again, to promote other contents or main sections of your blog: you can easily gain a second visit and maybe a second comment. For example you can list the most discussed articles or the most visited ones.


Replacement tags

There are few replacement tags you can use on emails to personalize the content, for example with the first name of the reader.

The name of the person which to message is addressed to
The email address of the person which to message is addressed to
The name of the author of the comment we’re notifying (to be used only on comment notification emails)
URL to the notified comment or the comment which generated the welcome or thank you email (the one left by the visitor)
The content of the notified comment (could be an excerpt if so configured on settings panel)
Then title of the post related to the comment we’re notifying or the title of the post related to the thank you email we’re sending. See even {post_url}.
Then URL of the post related to the comment we’re notifying or the title of the post related to the thank you email we’re sending. To build a link to that post use
<a href=”{post_url}”>{post_title}</a>
The URL to cancel the specific notification. To build a link use <a href=”{cancel_url}”>Click here to cancel from this notification</a>.

On first install, all messages are initialized with default content and there’s a reset button to restore the initial value if you suspect something is not working properly.

About links and the visual editor

When editing the message with the visual editor (it’s the WordPress post editor you’re used to) to create a link just select the words you want to link and in the request URL field use the tag. See the picture below.


Advanced settings

Comment trashing improvements

When a comment is trashed, other comments which are children of the one trashed are moved up and attached to the parent comment, if none.
Comment Plus can keep the comment thread coherent, deleting all the replies of a comment since replies of a no more existent opinion have no meaning.

User deletion

Comment Plus can delete all comments connected to a WordPress user when that user is deleted. Owned comments by the deleted user are identified with his user id and his email. That is rather useful when someone ask to be deleted and even the comments must be deleted.

Hide website field on comment form

Asking readers to leave their own website address is no more a requirement, so to make the form simpler you can set Comment Plus to remove that field. Note that WordPress still look for it on submitted data so automated systems that leave spam comments can anyway set it.

Form field labels translation

It’s not nice to have a comment form in English while the whole blog is in another language. For who has that problem with the installed theme, on Comment Plus configuration it’s possible to specify alternative texts for each comment form label.


Tech related

Messages template

Each notification, welcome and thank you messages share a common template, a frame, which contains the specific message text.
The template must a be a full HTML page and can be coded and configured in the template editing area.
Email templates are usually made of tables since old email clients cannot display correctly HTML content with more modern layout styles.
If you’re not used with HTML for emails, changing the template could be tricky, be sure to test your modifications on different email clients.
And remember you’re sending notifications and not marketing emails so keep them as simple as possible.

Adding manually the image/notification fields

If you need greater control on how the fields appear on the comment form you can add them manually. Below few example of the correct and minimal HTML code to add them. Of course the only requirement is to respect the field names and values sent when the comment is submitted, the HTML structure can be changed as required.
Of course you should add the labels as well.


General subscription checkbox

<input type="checkbox" name="cpsubscribe">


Replies subscription checkbox

<input type="checkbox" name="cpsubscribethread">


Image selection field

<input type="file" name="cpimage">


Styling the form fields

Form fields are added with a simple HTML structure and few style (CSS) classes so you can style them to better match your needs. Basic instructions to style forms and fields can be found here.

Image field

The HTML code for  is:

<p class="cp-image">
 <label>Add a picture...</label>
 <input type="file" ...>


The CSS rules you can use to change the aspect could be (these are only examples, more complex selectors can be used):

p.cp-image {

p.cp-image label {

p.cp-image input[type=file] {


Notification checkboxes

The HTML code for the subscription to all comments left on a post is:

<p class="cp-subscribe">
 <label><input type="checkbox" name="cpsubscribe"> Your label...</label>

and the HTML code for subscription to a comment thread replies is:

<p class="cp-subscribetread">
 <label><input type="checkbox" name="cpsubscribe"> Your label...</label>


Again an example of CSS selectors:


p.cp-subscribe {

p.cp-subscribe label {

p.cp-subscribe input[type=checkbox] {


It is recommended to always specify the type for input fields on CSS selectors to gain priority over default rules of the theme CSS. If you’re not able to adjust the field layout in your theme, you should contact the theme developer and ask how to address the problem.

Debug mode and log file

Comment Plus has a debug mode that can be activated to better understand internal operations and eventually discover errors. When in debug mode, a log file is generated and stored on wp-content/logs folder with name comment-plus-xxx.txt, where xxx is a random character sequence. Please do not keep the debug mode activated when not needed since it decrease the performances and creates huge log files!

The cache folder

Thumbnails and watermarked images are store in the cache folder wp-content/cache/comment-plus. If you backup the blog you can ignore that folder. It is a consolidated best practice among plugin developers to store cached files (which can be deleted as needed) in the folder wp-content/cache/(plugin name).



Notifications end to the spam folder

This is a reliability problem of your mail system, you can open a ticket to your provider to check if your server is blacklisted.
If you have an mail service (SMTP), install an SMTP plugin and configure the blog to send all the emails via that SMTP, this usually solves the spam issue.

No notifications are received

You should check if your blog can send emails. You can create a new user and activate the option “send the new user and email about their account” and check if the email is delivered. If not please open a ticket to your provider to check if your blog can send emails.

Image/notification fields show ugly

Usually this is a problem of your theme style (CSS). See the paragraph “styling Comment Plus fields” to know how to add your custom CSS. A web designer help could be useful.
Anyway do not miss to send us the link of a page where the defect can be seen since we could add more robust rules to our fields style to have them look nice even with your theme.

Image/notification fields do not show

First, check if you set those fields to be “injected automatically”. If not, set properly the option and check the comment form again. Be sure to empty any cache if you use one (at blog level and at server level, if required). If the fields still do not appear, probably your theme is using a custom comment form which does not fire the correct and standard WordPress events used by Comment Plus to inject the fields. You can ask the theme developer to update the custom form or add the fields directly to the custom form.

Attached images are not uploaded

If you have a plugin or a theme which uses AJAX to post comments, the developer maybe forgot to support attachments (technically multipart forms). He should update the plugin or the theme to use something like “jQuery Forms plugin” which supports the attachments even via AJAX.

Notifications are delivered as

You can change the sender email address and the sender name on Comment Plus main settings. If you use an SMTP plugin you can eventually set the sender values for all emails sent by WordPress in that plugin configuration and leave empty the Comment Plus sender configuration.