Can you explain why that would work? I’m not sure it addresses the core issue?:
The issue is simply that by sending down the images full size (and by full size that’s actually determined by the limit the Discourse engine sets up) you are using more bandwidth and more processing power on the client to then scale them back.
This is mitigated greatly by caching. So for a new user this is a big hit first time, then there should just be a much smaller delta as new topics are streamed. I cannot speak to how efficiently the local browser caches results of scaled images to optimise things though.
A modern fast computer on a modern internet link should have no issue with that, but a mobile computer, tablet or phone might have if they have not cached anything and are downloading the Topic List for the first time.
All that said, my iPad mini 4 on cellular copes completely fine with examples I’m aware of.
So I have not personally found it an issue at all and Tiles is not available as an option on phones presently anyway.
Only one user has told us recently that he would not use this feature as I believe they may have allowed Discourse to store very large images.
The proper solution is to update the codebase to scale image size whilst respecting the original aspect ratio. Presently the current thumbnail code, when set to do so, simply scales and crops to the chosen size, almost certainly losing the original aspect ratio of at least some of your images. This makes Tiles view more boring as it relies on variation in the aspect ratios for layout variety and in addition the cropping of course can make some of the images look awkward. Thus it remains the administrators trade-off.
This is “doable” and highly desirable, we just haven’t prioritised it.