Minecraft wiki entry for Custom_maps, associated text: A lot of textures can become very large without the benefit of improved quality. Some textures could be as large at 2048x2048 (almost 4K UHD) even if the player will never notice much difference. At most, textures should be 256x256 and they should not need to exceed this. Usually, textures can safely be in resolutions of 16x16, 32x32, or 64x64. Either way, try not to exceed 256x256, as this level of details is not easily be seen by the player. After finding an acceptable resolution, try using image compressors. These can sometimes reduce your file size by up to 90%, but may come at the cost of a loss of color depth (24-bit colors to 16-bit). This reduces the file size because there are not as many colors to store, but vibrant textures may become more "grainy", or "static-ey". If you still think there is data that can be shaved off, try removing all EXIF data from the image. Note that this will remove any copyright notes the image has (if any are present), and you may have to manually add credit (you should always give credit manually, but this is a legal matter).