The images are compressed, so they have to be decompressed and thus are larger. I assume that there are 4 bytes per pixel: R, G, B and Alpha. So for a 2048x2048-Texture, we have 2048 • 2048 = 4194304 pixels. 4194304 • 4 = 16777216 bytes for the uncompressed image. Or 16 Megabytes (/1024/1024). For a 4096x4096-Texture, it would be about 64 MB space.
So how to lower the ram usage? Make the textures smaller. (Not the quality, which is more of a compressing thing)
So how to lower the ram usage? Make the textures smaller. (Not the quality, which is more of a compressing thing)