Blocking if certain image is present possible?

[Trinsec]

I can block text-based content in comments and announcements in the Steam timeline, which works. But I now want to block a comment if it only contains a sole emoticon image. I haven't yet found a way to block the element based on an image, I've tried regex, link, etc options, but none of those could make the keyword match the image.

If I use a normal keyword for text, it works great. How can I make it work for filtering based on images?