One thing to consider that isn't often mentioned: if you don't feel like or are incapable of typing alt text - post toots without images.
If you think it's acceptable for blind & low vision folks to go without access to the image, then it's fine for everyone to go without.
You can simply toot your toot, leave the image off. I honestly do this a fair amount of the time when I'm too exhausted to create a good image description.
#Accessibility