Files won't optimize

• Check if the file format is supported
• A file may be larger if a certain algorithm is used, so Zap won't optimize a file if the end result would be bigger
• A file may have already been optimized
• Ensure files aren't read-only or in use
• Verify you have write permissions to the output location
• You aren't able to drag a folder containing images in to Zap to be optimized, only the files you would like to optimize

Optimization seems slow

• Large images take more time to process
• "Insane" optimization level is slower but achieves better compression
• Close other applications to free up system resources

Can't see optimized files

• Check the output mode setting (in-place vs. copy)