[SOLVED] Texture modding

I didnt know if to put it in the texture modding section, or here. I chose here seeing as how it seemed more fitting.

So I have been trying to edit the textures for the aa-12 all night and i have been following House Hax's tutorial to the t. The problem is, when i convert back to iwi (after editing the file) and after doing the CRC fix, the file sizes are different. Even if i try to use it, it crashes my game. It may be because i am trying it in SP, but that has very little to do with the fact that the file sizes are different.

Has there been some kind of fix for texture modding as of the new update? Or am I seriously missing something. Im about to try it with other files, but I fear Im going to get the same result.

I did the Hex editing exactly the same, and I know the two (original vs mine) look very different, but I did the copy/overwrite first two lines, then add the 4 00's then delete last 4 hexs, but nothing is working.

bleh.