Do 2048,1024,512 etc are a must texture size?

I want to make custom 2500 x 2500 wide texture.

do people accept that in market ?

It’s written in the guidelines at

2.3.7.a Both dimensions of each texture should have a size that is a power of 2 where applicable (e.g. 1024x512 or 1024x4096).

It’s not technically true that it’s a requirement any more, but it is strongly recommended. You won’t get mip-maps or anything else if your textures are not power of two.

For the marketplace I doubt there’s a good reason to upload a 2500x2500 texture.

Yes/no. I think if you have not power of 2 size, then multiple textures are packed into single texture.
For eg if you have 1 texture 1500x1500, it will be surrounded by some 500x500 textures.
At least this was the case with some older unreal engines. Maybe it is eliminated now.

To be really sure check NVIDIA and AMD limitations for texture sizes. No matter what game engine does, at some point it sends data to GPU.

I am confused.

i need simplified explanation. I am not that smart.

It’s a thing about how graphics cards work.
For 3D rendering, specifically, they are optimized to draw faster pixel buffers that are sized “power of 2” bits both width and height:

0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, etc…

So you can either have a texture square 2048 x 2048 or 2048 x 512, or 256 x 4096 and etc.

Any other resolution for height or width causes the GPU to do additional internal work to render that texture in 3D space.
Something like that, I’m not graphics programmer so I don’t know for sure what exactly happens inside the GPU.

So the 2048 stuff are preset within the fraphic card.

And if i choose 2500x2500 can cause lag ?

Like I said before, if it isn’t power of two, you won’t get mip maps. This will make it look ugly in game when viewed at certain distances.

oh i see. thanks.