You'll need to rip them from the sff files that are used for the MUGEN program (which is how I got them). Here's how...
- Get a program called MCM to do it (search for "mcm20b dev356" in Google), and the Street Fighter Alpha 2 background that you see in the gif I made (search for "Street Fighter Alpha 2 backgrounds + MUGEN" in Google).
- Once you have them, fire up MCM, and load the sff file that's used for the background (called "outback.sff" in the "Shin Akuma" folder if I recall).
- You'll get a boatload of sprites, some of which are the animated grass layers. Scroll through them using the slider bar to find the ones you want.
- From there, you can either export the grass sprites individually (one frame at a time), or you can export all of the background sprites that are in the sff file at once (these options are under the "SFF" tab along the top in MCM).
- Once that's done, you can load the exported .pcx files into Photoshop or Image Ready and work with them.
I'd post links, but I don't know if we're allowed to link to this kind of stuff on DA, so hopefully what I wrote will help.