For the very basic adjustments one could use this, completely free but with its restrictions:
https://www.photopea.com/
I use it every now and then when I'm at work and want to create a PNG i.e. to be used in a presentation.
@MementoMori started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
For the very basic adjustments one could use this, completely free but with its restrictions:
https://www.photopea.com/
I use it every now and then when I'm at work and want to create a PNG i.e. to be used in a presentation.