Generally images displayed on a page should match their served size. HTML scaling is not generally appropriate. Most page speed ranking services will also tell you this. https://developers.google.com/web/fundamentals/performance/optimizing-content-efficiency/image-optimization#delivering-scaled-image-assets They will even take it a step further and go into sprite use depending on your sites use of images. As it is, for years I have had to work around this in IPB by manually editing various templates, system files and settings to pull my images from a caching resize script. These are some of the optimization techniques I would rather see implemented in IPB. The example on page 1 of this thread is simply HTML scaled and is the same as the full size image. Instead of using 150KB it should probably use 50KB. If you have 10 images like this, now you're up to 1 MB of unnecessary extra transfer for the page.
When I use the default + sign, hardly anyone clicks on it or understands it. I have since replaced it with a huge green thumbs up with the word Thanks under it (about 8x bigger than the +). Doing this made the response rate go way up (probably 50 or 100x more than before). It would be good to consider something more like this.