Put the "provided by altbot" text at the beginning of the image description instead of at the end.

[luccaflower]

Some blind users have complained that they won't know that an image description was generated by altbot until their screenreader has finished reading the whole thing. Altbot image descriptions are incredibly wordy, so it often takes a long time for screenreaders to get to the end. By putting "provided by altbot" text at the beginning rather than the end, blind users who rely on screenreaders can elect to skip this particular alt-text, knowing that it will take a long time to read.