Obviously the classic app incorporating filters; an app you must know of even if you don’t use it.
Grungetastic
Love the filters on this app. They are different from any others I have found to date.
Download
Camera+
Another basic photo-effects app. Use it to become familiar with editing tools and expand the reach of your iPhone photo skills.
Halftone – Turn Photos Into Comics!
Sweet comic-book style/dotted retro photo filters with multiple backgrounds to choose from and bubbles/sayings/text to add.
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