this is a great time to get into writing IDs on your own posts btw!
because i've already seen etiquette posts going around saying that we should all start rbing directly from op so that op can see the engagement on their own posts.
but what's gonna happen is that now if there's a post with an undescribed image, a person who wants to reblog that post but also wants to be accessible is going to have to ask themself, do i just not reblog this post because it's not accessible? or do i add an ID in my reblog, knowing that this will reduce op's ability to see the notes on their own post? either way i'm leaving somebody out. but this problem is completely avoided if the original post itself contains any necessary descriptions!
if you are new to image descriptions and feeling overwhelmed, here are some things to know that might make it less overwhelming:
a "bad" or very general ID is better than no ID. if you made a beautiful painting of a sunset and know it would take you forever to describe it, well, there's a reason they say a picture is worth a thousand words! you can seriously just say "painting of a sunset" and that is so much better than nothing. even something this simple tells you what it is not. this short post by @mightyoctopus about the importance of adding even a simple ID says it really well.
for screenshots of text, there are handy programs that can convert images of letters into plain text! i don't use one so i can't really speak to this, but i'll link to a post in which @pathos-logical has linked to her favorite OCR tool.
or if it's easy for you to just copy and paste text into the post directly rather than taking a screenshot and then describing the screenshot, that might be less complicated. i know it really depends on how you're using tumblr, though - i imagine this is much easier on desktop than on mobile.
i have never encountered an ID writer who would be upset if op "stole" their ID and added it to the root post. in fact most ID writers actively encourage and even beg ops to do this. so if you do have a post that you posted without an ID and then someone adds one later, the next best thing is to copy and paste their ID into your original post. ID writers also do not mind at all if you edit their ID. and my sense is that it's also completely unnecessary to credit or @ the writer. just steal it! we don't mind!!
i'm not an expert on IDs so i will leave it there. and i do think it's possible to write IDs if all you know is the information in this post! it doesn't have to be intimidating, and it can improve not only other people's ability to engage with your work, but also (with this new tumblr update) your own ability to see that engagement.
if you are past the initial intimidation and want to learn more about the best ways to write IDs to accommodate the different ways people use them, i will just link to my image descriptions tag where i have collected the posts other people have made about this that i have found personally useful when writing IDs.
i have to run, hope this is helpful, bye!!