Steam – How to upload old screenshots taken with traditional methods to Steam

So, I kinda fixed the problem myself. First of all, I went to the game and made a screenshot while still in main menu, it appeared in another folder and with thumbnail and was visible in Screenshots Manager. So I just copied over the JPG files from steamapps\common\alien swarm\swarm\screenshots to (userdata)\remote\630\screenshots directory. Mine didn't have any thumbnails that I presume are needed for screenshot manager, so I just copied my screenshots in Thumbnails dir and batch-resized them to the thumbnail size (220xSomething). I also had to rename the files from asi-jac6-sewerjunction0006.jpg to 2011-10-07_00006.jpg and so on, but I am not sure if it was really necessary. After I restarted Steam my screenshots became visible in Screenshots Manager.

So I guess when you take in-game screenshots in Alien Swarm they are stored inside a game folder instead of steam folder. If you really want them published in your profile, you can do it manually like I did.

To view your friend's screenshots, your friend must first have saved said screenshots (obviously).

Firstly, you must view their Steam profile.

Secondly, you must click Screenshots on their profile page. It looks like this:

It should then bring up a list of all of their screenshots for your viewing pleasure. It will look something like this:

This all depends on whether or not your friend has his or her screenshots set as Public, Friends Only, or Private. If you know for a fact your friend has some screenshots, but you can't see them, the chances are they are private.