Free? Yes. Multiple platforms? Yes (Mac OS X, Windows, Linux). And now, perspective corrections (latest version is 4.05). How many times have I looked at a video and had a problem with perspective?

Many of the best photo editors have their own perspective control tools built in for correcting converging verticals and horizontals, but ViewPoint 5 goes further, with unique volumetric ...

Windows: Perspective Image Correction is a free Windows utility that will correct photos you've taken where the subject—like a building or monument—is out of alignment, or appears tilted.

You can also expect tools for correcting lens aberrations and fixing perspective issue such as converging verticals. As a first step into working with raw files, these programs are well worth ...

Upgrading to a full Adobe subscription is expensive (starting at $5 per month), but the subscription includes more advanced tools such as masking and healing, perspective correction, raw-file ...