Photo Power is a powerful photo processing too with a good array of features, it’s just been updated, you can check out What’s New below to see the new additions. It usually retails for $2.99/£1.99 but today it’s free. You can download it here. What’s New?   
# Multi-core processors acceleration (For iphone 4s+) 
# New feature: Auto Contrast
 # New LOMO: Smart BW
 # New share: Flickr 
# Improved UI 
# Improved performance 
# Improved Gradient Overlay algorithms 
# Fixed some bugs
# Modify some options in Settings 
# Automatically adjust the preview definition Existing Features ★ Base: Flip, Crop, Rotate 
 ★ Color Adjustment: Desaturate, Anti-Color, Complement Color, Hue/Saturation,…