[MoparFreak69]

I posted some pictures in the post your photos section and finally found a host that allows some ok sized images. I finally got them loaded and working right, but I see tons on image artifacting that I dont see from my original files that I shrunk down to upload onto the host. Any ideas of why its happening and how to prevent it?
Here is the posting I am referring to: https://www.pentaxforums.com/forums/post-your-photos/72737-some-firsts-my-own.html

[Marc Sabatella]

I'm assuming the artifacts come from the hosting service resizing your pictures, as they generally give you no control over that process. So if you tend to to like the results of resizing from a given service, the options would seem to be to either not let them resize your image (eg, upload it at the size you know they want in the first place), or switch to a different service.

[ytterbium]

Try flickr. It seems to preserve image quality pretty well and allows for hot linking. At least it does the trick for me. Only there is some size (1024px side?) limit if you have free account i guess. And it generates acceptable quality smaller sized versions as well:

[MoparFreak69]

Why does it seem that Microsoft Paint does a better job compressing large JPEG files than Photoshop? I have noticed light artifacting with Photoshop, but when I use Paint to make the file the same dimensions the artifacting isnt present. I have found that this light artifacting shows up really bad after I upload the pictures onto a host. Strange that Craprosoft can make something that works better than someone else?!

[Ash]

I'm not sure how you're doing your PS JPEG compressions, but this shouldn't be happening if it's being done right.
I've used the software for years and have never had a problem with JPEG artifacts.

[Marc Sabatella]

Why does it seem that Microsoft Paint does a better job compressing large JPEG files than Photoshop? I have noticed light artifacting with Photoshop, but when I use Paint to make the file the same dimensions the artifacting isnt present.

Most likely you have configured Photoshop to apply higher JOEG compression than Paint does. Compression level is user-selectable in Photoshop - you'll have to experiment to find the compression level that gives you the balance between file size and image quality that you personally find best. With a low compression (high quality) setting, you should get better results than Paint but with a larger file size; higher compression / lower quality settings will have the opposite effect.

[MoparFreak69]

Thats kind of what I was thinking, but the files generated by Paint are much smaller than any I can get with Photoshop, even on lowest setting, yet the image quality doesnt seem to be deteriorated. When I use photoshop to shrink my photos, I try to achieve the highest quality setting I can which is usually high, sometimes but rarely do I use med.

[Marc Sabatella]

Guess I'd have to see some samples to get a handle on it.

[Ash]

Even at medium JPEG compression on PS, I get crisp images with no noticeable artifacts when viewed on screen.
Are the originals coming up on PS without artifacting?
Post up some examples with compression amount, image size and any applied PP data for us to see...

[dragonfly]

Maybe you only need to resize your images and not compress them using JPEG.

[photog]

Does Microsoft Paint resize the image as well as compressing it?

[MoparFreak69]

Sorry I havent been able to upload any examples yet. I use Microsoft Paint only to shrink the photos as there is no option for changing compression. The only real way to resize the image is to shrink it to certain % of original size which I usually go for about 20 percent. When I use photoshop to resize the photo I usually take it down to 1024 by whatever the linked aspect ration pixel size would be. I then save the photos at high quality which would be minimal compression. I get the artifacting only in Photoshop even though the images are pretty close to the same pixel size.
This first picture was resized using Microsoft Print at 20% which brought the pixel size to approx 934x621. The file size is about 158kb

This photo was shrunk using Photoshop CS4 Extended to 20% which it says was 935x621. File size was 151kb.


Both resized from an original Jpeg.

[Marc Sabatella]

Hmm. Not sure what may have contributed to this, but I see two things going on:

- Paint version has less obvious artifacting, as you noted
- Photoshop version retained more detail (look at plants under umbrellas in lower left, mural on wall, etc)

So it seems to me that Paint did a terrible job in resizing, losing quite a bit of detail, which allows compression to work more efficiently. So it's probably applying much less compression in order to get that same file size than Photoshop is.

Presumably, there is be an option in Photoshop to make it do a less good job of resizing, and then you'd be able to use a lesser amount of compression on that file and still get the same filesize, assuming you don't mind trading artifacts for detail. Personally, I'd be keeping the resizing the same in Photoshop and simply going with less compression, even if that meant a larger filesize.