Final Fantasy Discovery

Hey guys, I recently downloaded the iOS game, Final Fantasy All The Bravest. It's a realllllly crappy game that Square Enix put out, seemingly with the sole purpose of insulting their fans...

However, the game does come with some new battle sprites of monsters previously unseen in a 2D format (like enemies from FF7, FFX and FFXIII). I've ripped a bunch of them, but there's a small issue. They are basically shown on the iPhone screen at 2x, and they had to be ripped that way.

The problem is, whenever I resize them (even though the canvas is equal in both width and height), the sprites come out all distorted, which makes NO sense to me. Anyone else ever have this issue when resizing a sprite. I've never run into this issue before. If a sprite was 100 x 100 pixels, and I resized it to 50% (it's intended size), it always came out A-OK.

These just... don't. Of course, I could replicate them myself at their normal size, but that'd take a ton of time. I've tried it in Photoshop, Paint and GIMP and the result is always the same.

I'd love to be able to complete this set and include them in the game (and release them for the community to use). If anyone has any insights on a fast fix, let me know!