I tried that and it didn’t work. It may have been the size of the (raw) file. I reposted with a smaller file and that worked.
You wouldn't want to post a RAW, it's not a display format for sharing images. And, as you experienced, the size in bytes likely would exceed the 20MB limit for file attachments.
You wouldn't want to post a RAW, it's not a display format for sharing images. And, as you experienced, the size in bytes likely would exceed the 20MB limit for file attachments.