I've been trying out several different programs to create short gif loops from my SFM projects. However despite experimenting with different resolutions and lenghts they always end up pretty bloated. Usually at least around 70mb for a 1280x720 resolution three second loop, not to mention the quality that tends to suffer significantly alongside it.

I'd like to know what people are using to create those high resolution and smooth high quality gifs with small file size (roughly 5-30mb). Any help would be much appreciated.

Also, does this site support gifs playing at 60fps?

GIFs never play at 60fps, but ~50fps is possible (0.02 sec delay between frames).

GIFs will always degrade the quality of SFM animations and almost always have large filesized due to the compression method used, though having custom pallets for each frame helps a bit. WebM is a far better choice but this site doesn't support it yet. APNG will preserve the quality but still give you massive filezise. GIFs using "nearest color" conversion instead of "dithering" are usually smaller but tend to look worse. Setting an option to crop redundancies from each frame cuts the filesize down as well.

As for best program, I don't know, but I hope what I said helps a bit.

I think a lot of people just use photoshop to make GIFs. I use photoshop and also a program called GIFcam...but then I usually take the output from GIFcam and edit it in photoshop.

Also, I've noticed that the GIFs I have that are 1280x720 with a small file size have just a few frames...around 30 frames, which isn't much. If your animations are long it'll be tough to turn them into GIFs of that image size while also keeping the file size under control. You'll have to sacrifice something in order to keep the file size down, whether it be frame count, image size, amount of colors, etc. Or just make a massive-ass GIF and upload it to GIFYcat which will convert it to a webm for you.

Another thing you could try is just going to the tumblr of one of your favorite SFM artists who are already making those types of huge GIFs and asking what they do. They might tell you to fuck off or they might actually give you an answer.