Only a single program was used to safely compress all textures in MTG.
This was done using optipng with the following settings:
```
optipng -o7 -zm1-9 -nc -strip all -clobber %%f
```
The key command used is -nc, which stops color mode changes. I.e. any RGBA textures will remain RGBA textures, with none being changes to 8-bit indexed mode.
The resulting compression:
| type | size (Bytes) | % of original texture size |
| --- | --- | --- |
| Original | 247,571 | 100% |
| Compressed | 152,189 | 61.5% |
**Summary: Saves 93.14 KB**
A script has been added: utils/optimize_textures.sh which will perform this compression automatically, assuming optipng is installed.
Some GPUs cause visual bugs when mip-mapping is used with indexed textures
that use alpha. Because leaves are sometimes rendered opaque it is even
more important to keep these as RGBA to preserve the correct background
colour.