I blame you for the recent downtime.... You're welcome.
This should now be a usable option for you on this main Lemmy-UI. Go to your settings and uncheck the Show images in posts and comments option. Save, and then CTRL+ F5 the website to load the new settings. You should not have any thumbnails or images in posts or comments.
This only changes it for our main UI, nothing different for apps or old.beehaw.org.
there isn't, but there should be! besides the readability and metered-bandwidth benefits there would also be a privacy benefit in having this feature (as you reveal your IP address and what you're reading to 3rd party servers whenever someone links externally-hosted images).
You might be able to use NextDNS to block various third-party servers which are popular for hosting images.
A little fiddly to set up, as you'd need to create a custom block list, and you won't catch all of them, but you should be able to eliminate most of it.
It's nice & light in itself & though it is mostly used to reduce tracking across the internet, it could work well for reducing data generally.
If you are using an Android phone, uBlock Origin as wn extension to Firefox could also be of interest to you (can block images over a size you set, and allows fine-tuned exceptions per site).
Ah, in that case I'd recommend using Sync for Lemmy. Sync has options to turn off emdedded images, as well as several data saving features (such as disabling preloading etc).