As the topic says, if you are uploading images please don't save them as multi-pass progressive JPEGs or interlaced PNGs. If you don't know what this is, it's an image that loads a pixelated base and then slowly refines it as the image is loaded in multiple passes instead of the more traditional line by line approach.

The reason I request this is because Firefox's color management takes a huge performance hit on those type of images. On normal (non-interlaced) PNGs and JPEGs there is no issue. This will soon become an major issue for all Firefox users as Mozilla is quickly moving towards enabling color management by default on all images (they already have it enabled for tagged images in the nightly builds) and who knows if this performance problem will be fixed by then.

Is http://moe.imouto.org/post/show/40734 an example of what you are referring to?

I've seen a few of those, but it loaded fine to me so I never bothered with them.

works fine for me, too

Radioactive said:
Is http://moe.imouto.org/post/show/40734 an example of what you are referring to?

Yes, ones like those. I never said they don't work, just that that have a huge performance hit if you enable color management for all images in Firefox 3.0-3.1.

If you have Firefox 3.0.x go into about:config and set gfx.color_management.enabled = true OR download a 3.1 nightly and set gfx.color_management.mode = 1 and then try loading the image. Instead of taking less then a second with color management off, it will take around 7-25 seconds (depending on image size and dimensions) while maxing out a CPU core and lagging down or even hanging the whole browser completely until it loads the image.

Do you have to no matter what upload images in an interlaced format?

Is there a reason, that especially with people who upload there own scans or clean scans to upload these multi-pass images?

I would like to be able to keep color management on in Firefox so I see the correct colors on images with embedded color profiles and when I run into the rare (likely only 1-5% of all images) progressive JPEG or interlaced PNG uploaded on moe, the performance hit weighs out the benefits.

This is just a kind request to when possible (without quality loss) to upload an image as non-interlaced, to do so for others, like me, who may want to use color management in Firefox.

Maybe starting to tag those images with an "Interlaced" tag might be an alternative solution if people must continue uploading images in that format considering they are rather rare to begin with. Having images tagged as such would act as a warning to steer clear of trying to view those images full-size before downloading and instead just download them directly and view them outside of Firefox.

Cyberbeing said:
Yes, ones like those. I never said they don't work, just that that have a huge performance hit if you enable color management for all images in Firefox 3.0-3.1.

If you have Firefox 3.0.x go into about:config and set gfx.color_management.enabled = true OR download a 3.1 nightly and set gfx.color_management.mode = 1 and then try loading the image. Instead of taking less then a second with color management off, it will take around 7-25 seconds (depending on image size and dimensions) while maxing out a CPU core and lagging down or even hanging the whole browser completely until it loads the image.

Do you have to no matter what upload images in an interlaced format?

Is there a reason, that especially with people who upload there own scans or clean scans to upload these multi-pass images?

I would like to be able to keep color management on in Firefox so I see the correct colors on images with embedded color profiles and when I run into the rare (likely only 1-5% of all images) progressive JPEG or interlaced PNG uploaded on moe, the performance hit weighs out the benefits.

This is just a kind request to when possible (without quality loss) to upload an image as non-interlaced, to do so for others, like me, who may want to use color management in Firefox.

Maybe starting to tag those images with an "Interlaced" tag might be an alternative solution if people must continue uploading images in that format considering they are rather rare to begin with. Having images tagged as such would act as a warning to steer clear of trying to view those images full-size before downloading and instead just download them directly and view them outside of Firefox.

From my point of view..this is just ur personal preference(personally..i dun see anything wrong, or slowdowns). People upload scans cuz they want to contribute to the community, but it's up to them if they want to upload a interlaced image or a gigantic tiff. You might have a point that interlaced images are kinda strange, but it's not like moe is full of them. As i see there's no rule about not posting interlaced stuff. Just use a different browser and re-save it.

I should probably make clear that I am not trying to order people around or make rules. This is just a peaceful request with a reason why. All this is about is making it easier for uploaders making an educated decision in what format they choose to upload. I updated the thread title to reflect that better.

This issue does exist for interlaced images with color management enabled in Firefox (see bug report on bugzilla), but won't truly be a major issue until Q1 2009 when Firefox 3.1 is released with Color Management on all imaged enabled by default (if the issue isn't fixed first).

It is ultimately up to the uploaders to use whatever format image they chose and I'm not disputing that. I made this post to make people aware that there is an issue for some people and it would be nice if they would avoid uploading images in a potentially problematic format.

Interlaced/Progressive formats are never the default anyways so people are making a conscious effort to chose them but may or may not understand the implications of doing so.

It is currently my personal preference to use Color Management in Firefox (when 3.1 is released this will no longer be the case). Interlaced/Progressive images on the other hand may or may not be the personal preference of an uploader. I have a feeling that most are rather indifferent on the issue and wouldn't have an issue avoiding interlaced formats.

PNG is lossless, so saving an interlaced PNG to a non-interlaced PNG is also lossless is shouldn't be an issue to do before uploading. So from a quality standpoint there is no reason to upload an interlaced PNG image. Now if the uploader wants to take the time do this is ultimately the decision of the uploader and many may decide not to and that's ok.

JPEGs are a different story though considering they are lossy. Some images come from sources other then the uploader and may be in progressive (interlaced) format. For these outside images there is no point in re-saving them as non-interlaced and sustain more quality loss to the image so should continued to be uploaded as-is.

whats the advantage of FFs color management to begin with??

http://en.wikipedia.org/wiki/Color_management mentions FF

With color management enabled it allows images in Firefox to look identical to how they would in Photoshop. Basically that means you're able to view images (with embedded ICC color profiles) as they were intended to be viewed.

The blog post here describes it and has examples: http://www.dria.org/wordpress/archives/2008/04/29/633/

I've been having this enabled for a while, so long that I can't even remember when I changed it.
gfx.color_management.enabled = true

is that? if it is I don't notice any major issues loading a high res with progressive or not. Same "slowdown" for processing the image if you can call it like that

Seems from my point of view. The color support increases tone and saturation, but detail is not loss.

Usually that will be the case, but not always.

Here is another page that might be worth reading with some tests for color management support:
http://www.gballard.net/psd/go_live_page_profile/embeddedJPEGprofiles.html

Shuugo said:
I've been having this enabled for a while, so long that I can't even remember when I changed it.
gfx.color_management.enabled = true

is that? if it is I don't notice any major issues loading a high res with progressive or not. Same "slowdown" for processing the image if you can call it like that

I just switched mine over to ENABLED, and DID notice a difference when I opened http://moe.imouto.org/post/show/40734 - The browser hung for about 3 seconds before the scan started to appear.

Radioactive said:
I just switched mine over to ENABLED, and DID notice a difference when I opened http://moe.imouto.org/post/show/40734 - The browser hung for about 3 seconds before the scan started to appear.

Yep, that is the performance problem I was talking about.

Not sure there is a lot we can do about that. It is really down to Mozilla to optimise their color management for interlaced/progressive images.

How well does Safaris color management compare?

For the moment I can only recommend you tag an image with 'interlaced' if you come across one.

I have never been very fond of Safari so I haven't tested it, but I'm assuming this is likely a Firefox only problem.

The only thing that can be done is avoid interlaced/progressive images when possible. I do really hope Mozilla fixes it sooner rather then later to make this issue mute.

Radioactive said:
For the moment I can only recommend you tag an image with 'interlaced' if you come across one.

I would have no problem tagging images I come across with an 'interlaced' tag as long as admin2 and/or petopeto are okay with it.

I would have no problem tagging images I come across with an 'interlaced' tag as long as admin2 and/or petopeto are okay with it.

On second thoughts, maybe a bit much for a isolated, possibly short-term, issue. I'm sure admin2/petopeto will give you some feedback.

Safari ( well, my nighlies of Webkit from last month ) loads the progressive JPG like a standard JPG. Then color wise, the ICC profile is loaded, and look the same as in Photoshop or Firefox 3 with color management for ICC.

ICC profile is useful when you get file from a scanner or a camera since there are different setting for each of them. It allows to display the image evenly on any OS / software / hardware. But from my experience it's quite bothersome because some software doesn't support them natively, so what you see in Photoshop is not what some other people will see...

I don't think "Firefox just became much slower" is a very good reason; that's their fault and if they release knowing it's so much slower, they're screwing up. (If they can't do this without making the browser slower, they need to turn it off by default for those images.) There are other reasons why progressive images sort of suck, though. They're intended for slower connections--an old feature for modems--but they're just ugly and annoying for modern connections, which is probably what you have if you're viewing the full-res images here live.

That said, I wouldn't recompress interlaced JPEGs just to deinterlace them. If I'm tweaking an image for other reasons, I try to remember to switch interlacing off, though.

The image samples don't currently have support for color profiles.