[Graphics] Pokemon GBA Rom Hacking Problems

Ok so about 8 months ago I started to work on my first Pokemon Rom hack and I used an original Emerald rom to start and went on from there. I started small by changing the wild pokemon and trainers, but then I got into more difficult things such as changing sprites and editing pokemon stats. Everything was going fine until one day I used a program called unLZ I believe to change trainer sprites(since Nameless Sprite Editor doesn't support emerald for trainer sprites.) So I changed a few sprites and it looked bad so I changed the sprites to some random place holder sprites, then I took a break and when I re-opened unLZ, I couldn't find any of the place holder sprites and here's an example of what I'm talking about (Original emerald rom compared to my rom hack)(Check the images that show unLZ with the different roms for more details about this problem) And the sprites come out looking like the placeholder sprites I used. (see the other image to know what I'm saying)

ANYONE PLEASE HELP I WANT TO FIX THIS BEFORE I RELEASE THE ROM TO THE PUBLIC!!!

Welcome to the community! Unfortunately I am not the best at these questions, so I would post them in our ROM hacking section on the boards, which you can find here on the main page! Good luck in your search, but I think you'll find most people will want to help you if you ask nice enough!

well, first of all, you need to export the image to edited in paint. Later you edit it with the color of the image, no other colours. then when you need to save it, you need to be carefull. don't put "automatic fix pointers" and do not deselect "autoabort if data is to big". the others 2 deselected too. and also, maybe you need to learn some of code of pokemon, because replace an image i'ts make the game to crash some times. If you learn some code, it's better to add things and then delete the others. It is hard at first, but then is more easy and the results are better.