The inbuilt generate feature for Photoshop is very useful.
You can export layers and folder quickly by simply using the correct naming syntax.
File Format
.png (Default value: png32 with semi-transparent alpha), .png8, .png24, .png32
.jpg (Default value: 9), .jpg(1-10), .jpg(1-100%)
.gif
File Sizing
200%
250x250
mm cm in
Folders
myFolder/HiRes/
Complex naming string Example.
200% myFolder/HiRes/Logo.png, 10mmx10mm myFolder/LowRes/Logo.png