Free equivalents to Photoshop for this task?

[dinamow]

I'd like to edit a photo, to add symmetry to an asymetrical smile (don't judge, it's an experiment!). I know that it's the sort of thing Photoshop can do, so I'm tempted by the 7 day free trial, but before I go ahead and give Adobe my credit card details to start the trial, does anyone know of a free tool that does the same job?

(I can use Paint to clip and flip the mouth, but it looks odd because the two sides of the face have different amounts of shadow, so I need something more sophisticated).

On a laptop/pc use GIMP - can do most of what photoshop does.
Phone app, try Lightroom.

YY to Gimp. It can be a bit difficult to use if you've never used photoshop, but the online help file is fairly good.

Just use Facetune it's dead easy!

Airbrush has some free features.