Just for reference:

The #Tootle app does not have an option for adding ALT-TEXT to images and has an NSFW option.

#MastodonOfficial does have the ALT text option but no CW or sensitivity option.

#Tooot has the ALT-text option and can also be marked as #Sensitive

My web browser allows for #ALT-TEXT and media can be marked as sensitive.

Now you know!