Texture replacement issue

[Danikk04]

I have tried out the texture replacement feature in SD Gundam G Generation Overworld in order to use higher resolution sprites ripped from earlier games (PS2) in the series.
The issue I'm having is that most sprites in the game are 384*384 or 192*192 in size, and PPSSPP dumps them as 512*512 or 256*256 with random junk filling out the rest of the image. This is an issue, because if the random part of the sprite is different, the image will have a different hash for its data, and since the address changes every time the sprite is loaded as well, it means I can't "lock on" onto a given sprite for replacement. (since the only thing staying constant is the CLUT)
Is there any way for the emulator to detect the real size of the sprite and output it in that size (or at least clear the rest so it will always be the same)?