Is it time to eliminate the "Progressive mode" checkbox on Settings / Images? A lot of image expander scripts can't handle it, and I'm not sure it serves a useful function these days. It has virtually no effect using scaled images, except perhaps on the worst of dialup connections. Even with large originals, I question the value of having the image appear blurry, then gradually sharpen. Is that actually better than having the full-res image render from the top down?
Is it time to eliminate the "Progressive mode" checkbox on Settings / Images? A lot of image expander scripts can't handle it, and I'm not sure it serves a useful function these days. It has virtually no effect using scaled images, except perhaps on the worst of dialup connections.
I have poor connection and I use this setting.
Even with large originals, I question the value of having the image appear blurry, then gradually sharpen. Is that actually better than having the full-res image render from the top down?
I'm open to contrary opinions.
I hope it is ok to answer to such an old thread. Taking into account that the answer from jGromit a couple years old I assume, that with today's bandwidth this option is definitely of no use. If this is true, so why not get rid of that option? Or to add a sentence in the online help that this option is not necessary if bandwith is not a limiting factor.
Ironically, it makes less difference than it used to. Progressive mode really made a mess of Flash skins, but those are disappearing. The image expanders in non-Flash skins like Turtle, Matrix, and Photoblogger aren't thrown by it. I haven't tested other current skins.
If no one objects, I'll remove this feature from the next version.
The option is still there, over three years later, and over ten years since the original request.
I don't think progressive mode JPG's hurt anything - I don't think there's any skin that gets thrown for a loop by them. In fact, I think that with some of the expander scripts being used in current skins, it is ineffective, even with limited bandwidth. But I'm always in favor of removing options that aren't needed, just to keep the UI stripped down.
And I've long suspected that people choose Progressive mode because they think it's more modern and forward-looking than the alternative, which must be regressive mode.
I did some tinkering with this. It's tough to test when you've got 110mbps download speed, but I put some grossly oversized images on jalbum.net, where the transatlantic hop introduces some slowness. The "progressive" effect was barely noticeable. On a totally non-responsive slide page, it still "painted" the image from top to bottom, but with some mild pixellation, and then quickly sharpened it up. But the difference between that and a baseline JPG loading on the page was almost undetectable. It would probably make some difference on a dial-up line, but I haven't seen a Hayes modem in ages.
And with some image expander scripts, the script probably doesn't display the image until it's got the whole thing, since it often wants to apply things like transition effects. In that case, there would be no difference between progressive and baseline.
I've read some recent posts online about how progressive JPG's speed page loading, but most of it sounds like theoretical nonsense, stuff that doesn't reflect real-world experience. There is also a theory that the appearance of a pixellated image followed by sharpening, while it may be a few milliseconds faster, is actually perceived by site visitors as being slower.