There is currently no way to automatically populate Photo Center's Alt Text field upon upload. I would propose that the Alt Text field added to IPTC/EXIF/Photo Mechanic in 2021 be mapped directly to Alt Text field within Photo Center upon upload.
I see something similar was proposed in ANG-I-191 and agree the caption/title/existing field should not be mapped to Alt Text; hence the suggestion of its own field.
We are contemplating pursuing an AI solution to generate alt text for images, which could be exported to a spreadsheet/XLS and automatically added to a batch of photos in Photo Mechanic prior to uploading to Photo Center. Having the Alt Text fields in IPTC and Photo Center would be key to that project however.
Brian McAlister
