gimp-lomo

A Script-Fu plugin for the GNU Image Manipulation Program, to apply a Lomo LC-A effect on your photos.

Installation

Download and install The GIMP on your operating system.
Identify one of the Script-Fu folders by checking Edit > Preferences > Folders > Scripts
Download the script and place it in one of these folders. This is a script written in the Scheme language, pretty cool if you ask me!
Filters > Script-Fu > Refresh Scripts
Open an image and Select All (Cmd/Ctrl-A)
Then Script-Fu > Utils > Apply Lomo LC-A Effect
The defaults are usually pretty good. Feel free to play with the input parameters in the dialog box to adjust saturation, contrast and vignetting.
File > Export to flatten and save back to JPEG (otherwise GIMP would save in its very own XCF format, which keeps track of individual layers, palettes and whatnot)

Like it? Use hashtag #lomogimp in your social media posts!