IMPORTANT NOTICE: Only links from  https://i.postimg.cc  are treated as valid now. This is due to a security oversight that allowed for IP grabbers to be used as valid image links. I am sorry for any inconvenience this may cause. If you do not mind the risks that this poses, you may use the archived 1.0.0 version of the mod.

This mod converts postimages.org image URLs to images in chat. 

Main Caveats: 
The images will only be seen by those who also have the mod.
The image must start with https://i.postimg.cc and end in .jpg|.png|.webp . 
The image URL must be 80 characters or less (Valve chat length limit).

Tutorial:
Go to postimages.org
Choose an image to upload, either by using the "Choose Image" button, or clicking on the "Upload via URL" button and pasting in a URL. This will take you to a page that says "Upload Complete". You can then copy the "Direct Link" and use that.
If the "Direct Link" is too long, hover over the image. A gear-shaped "Settings" icon will appear. Click on that, set the name to something short (doesn't matter what), and reload the page. The "Direct Link" should now be short enough to paste into chat.

Known Issues:
Large images take a while to load - nothing I can really do on that end
GIFs don't work - Valve limitation, even if I do allow them, it'll only show the first frame.