Larger size limit for image host

[Wile E]

To add to that...

GIF = best for images with 256 colors or less.
JPEG = best for images with lots of variations (virtually all digital camera pictures and game screenshots).
PNG = best for images with large areas of a solid color (like a screenshot of this website).

You should always be able to get a 1920x1200 picture under the 2 MiB limit with the right format. I've only encountered problems with size when dealing with 5+ megapixel pictures from digital cameras. In which event, I either crop or scale the image down and save as JPG (PNG generally won't work well for something photographed) and then they usually come in under 1 MiB.

Yes, it's more work to treat images right but it's also easier on everyone else (bandwidth, hosting server, users viewing it, etc.) to do so.


As such, I think the 2 MiB limit is fine for the time being. Yes, it can be a bit annoying but it is for the better.

I completely disagree with your assessment what png and jpeg are best for. I think png is the best format for comparisons. Jpeg is great for just showing stuff without the need for absolute accuracy.

That said, there have been some great suggestions in this thread on how to maintain accuracy while achieving good compression.


EDIT: And I forgot to ask Newtekie a question: What software do you use to compare the photos?

 

[slyfox2151]

EDIT: And I forgot to ask Newtekie a question: What software do you use to compare the photos?

+1 i would also like to know

 

[qubit]

With today's high res screens, I was wondering if maybe we can have a larger file size limit on tpu.org, so we can host those larger png's from gaming screenshots and such?

I think the limit should be left as it is.

If you need to make a gaming screenshot and you don't want to lost picture quality due to jpeg compression and/or resizing artifacts, then simply use a smaller display mode for the screenshot and save it as lossless png.

Using 1024x768 or 1366x768 resolutions will give you plenty of detail for a forum post. In fact, if you're comparing something like antialising between different screenshots, using a lower res will actually show up the differences more.

If someone really does need to display a large image, then they can always host it elsewhere and add it as an attachment or link to the post, perhaps with a small version embedded in the post as a preview.

If you want real easy image manipulation, then Google's free Picassa application is great.

How does this sound to you?

 

[Wile E]

We have already had quite a few good suggestions. How well does Picassa do lossless?

 

[qubit]

We have already had quite a few good suggestions. How well does Picassa do lossless?

It's a good program. I have to confess that I've only used it for a couple of minutes myself as I don't do much with pictures, but my friends who've used it have said it's pretty good.

Hey, it costs you nothing to try it and see if you like it.

 

[newtekie1]

I don't have photoshop, and most of us can't afford that, so while providing us with a great proof of concept, that method is not really doable for most of us.

It wasn't meant as a general method, it was meant to show that a format that most put off as lossy and un-suited to the purposes you've described isn't always the case. However, GIMP could be used in place of Photoshop, as it also offers a 100% quality setting for jpg images that gives the same results as Photoshop and is free. I just used Photoshop because I'm more comfortable with it, and that is what I had installed.

EDIT: And I forgot to ask Newtekie a question: What software do you use to compare the photos?

The software is called Beyond Compare. The settings I used had the tolarence set to 10(default of 25). Now how the tolarence works is with each pixel, if the color between the original and compared picture is 10 RGB color points off it is highlighted. Generally anything less than a 25 point difference is considered invisible to the human eye, humans can't tell the difference between shades that close.

 

[FordGT90Concept]

I completely disagree with your assessment what png and jpeg are best for. I think png is the best format for comparisons. Jpeg is great for just showing stuff without the need for absolute accuracy.

Generally anything less than a 25 point difference is considered invisible to the human eye, humans can't tell the difference between shades that close.

Exactly why I don't use JPEG for solid colors because it makes a mess of it. On pictures with lots of variations, the only way one can see the JPEG loss is by zooming way in. On things like faces, trees, and other scenery, it is virtually impossible to tell the file was ever saved as a JPEG. Again, solid areas are the give away and PNG does a good job at them compression wise.

PNG is lossless, JPEG is lossy. There's instances where the lossiness of JPEG doesn't impact the image quality enough to forfeit the space savings, as newkekie pointed out.

If you need "absolute accuracy," it probably shouldn't be on TPU.org because it will always add the watermark anyway.

 

[newtekie1]

Exactly why I don't use JPEG for solid colors because it makes a mess of it. On pictures with lots of variations, the only way one can see the JPEG loss is by zooming way in. On things like faces, trees, and other scenery, it is virtually impossible to tell the file was ever saved as a JPEG. Again, solid areas are the give away and PNG does a good job at them compression wise.

PNG is lossless, JPEG is lossy. There's instances where the lossiness of JPEG doesn't impact the image quality enough to forfeit the space savings, as newkekie pointed out.

If you need "absolute accuracy," it probably shouldn't be on TPU.org because it will always add the watermark anyway.

Even with solid colors, generally the human eye can not tell the difference between two colors that are less than 25 RBG points away from eachother, however I still think some people can which is why I lowered the tolerance to 10 RGB points, because I'm pretty sure even if you zoom way in and pick just one pixel and make it the size of the screen, no one can tell the difference if they are only 10 RGB points off.

 

[FordGT90Concept]

I just did a quick experiment in MS Paint which had serious problems with making a mess of things in the XP edition. It appears they made some changes in the Win7 version because the mess is not at all visible without using the fill tool, even at 800% zoom. PNG was still far more efficient though file size wise. I attached it if anyone wants to have a peak (100x100 pictures with a 25x25 black square).