All item, armor, weapon, skills, and any other icons are 24x24 pixels. As for character sprites on the overworld, they usually tend to be 32x48, but you can make them bigger or smaller if need be. Custom tilesets use 32x32 per tile. Battler sprites are a little tougher, as they can be just about any size you want.

If you want to know exactly what size a sprite is, you can rip it directly using the Materials/Materialbase window (located directly right of the Database) by going to whichever folder you need, finding the sprite you want to export, and hit the "Export" button, and this'll allow you to export the sprite directly, allowing you to view all of it's properties.

As for actually making the sprites themselves, I personally recommend Piskel (https://www.piskelapp.com/). It's free and can be used online or can be downloaded. I'm pretty sure it's even open source (if that matters to you at all lol). There's plenty of others, but I find this one to be the easiest to use.

Once you've actually made a sprite, you can just download it directly to Documents -> RPGXP -> (Your game name) -> Graphics -> (whichever sprite type you've made, items will be in "Icons")

Some Guy Named Gerald

Hi, I'm wondering how to change the sprite sheet size, I know that other games have files that point out where the sprites are to the game. I am sorry if this is confusing. If you change the sprite sheet size, how do you let RPG maker know where the boundaries of the sprites are. can you even change the boundaries of the sprite?

Originally posted by PigOrbitsEarth1:

Some Guy Named Gerald

Hi, I'm wondering how to change the sprite sheet size, I know that other games have files that point out where the sprites are to the game. I am sorry if this is confusing. If you change the sprite sheet size, how do you let RPG maker know where the boundaries of the sprites are. can you even change the boundaries of the sprite?

I'm assuming you're asking how to add additional frames to a spritesheet? To my knowledge, I don't think there's a way to do this without scripts, and even then, this is something I've never attempted, and unfortunately cannot help with.

If what your looking for is to just make all frames of a given spritesheet larger in size, then it is important to remember that every spritesheet functions like a grid. For instance, overworld character spritesheets are 4 frames by 4 frames. So, let's say you wanted a 64x64 pixel sprite. The spritesheet's total size would equate to a 256x256 pixel image. The boundaries of each frame are each 64x64 space in this example.
I hope I explained this in a way that makes sense, lol