esuDesuTalk is a userscript that allows you to hide text within images.
How to use: https://github.com/desudesutalk/desudesutalk/wiki/How-to-use-this-script
Apparently it's very popular with Russians and or the Russian chansphere.
For some reason it doesn't work with 4chanX if you enter anything in your reply, so just dumping images should be fine and simply scanning the images doesn't interfere with 4chan x either. I tried posting it in the OP image but it didn't work for some reason. Here's what it would have said:
"o you read me? Testing testing 1 2 3.
One of the shortcomings is that the post doesn't automatically timestamp your post, so people could repost an image without knowing that there's a message inside it and people with the script might think the poster was using it.
I thought it might be fun for some people to use on /qa/, maybe even a way to add some flavor to certain threads.
Some other techniques previously discussed on /qa/ that dealt with hiding things in images, if you missed them, was making the thumbnails different than the actual image and discovering that png images can have their colors saved in the transparent parts.
I haven't tested this with the former but I know that desudesutalk does not preserve transparency and will make the background white; this is probably due to the programmer not considering transparency or the cryptography algorithm can't preserve transparency.
I know that a while ago some people were using this on /bant/ and others use it on /g/ but it's infrequent anywhere else."