I generated a tilemap from a large orthophoto using gdal2tile. Looking at a file of 256x256 at dense areas, file sizes above 150kb.
This adds up a bit when loading many tiles when i compared to bingmaps etc (below 100kb) .
Tested a few tiles, i converted it to PNG 8-bit format using paint.net
Visually it looks the same but the file sizes are 1/3 of the original.
My question are
Is it accepted to use 8-bit PNG. The original file is a colored orthophoto of a city.
Reading up on transparency, it seems 8-bit supports it. It is needed in my application.