Replace the image custom size input text
In an attempt to increase usability
We could replace the selectbox/combox with the following values (in GB):
- 8
- 16
- 32
- 64
- 128
- 200
- 256
- 512
Probably these numbers should - in reality - create image a bit smaller that this to be sure we are able to write them on all physical SD cards. (wo maybe just remove a few percents)