Compression on Uploaded Photos

[Bruce]

When I compare the database version with the one I uploaded from my computer, I can see some degrading of the image. Looks like jpeg compression to me. It kind of makes some of the photos look worse when viewed online. Has anyone else noticed this?

[Leftseat86]

Thank you Bruce!!!! I thought I was the only one noticing this. I get the same thing you described.


-Clovis nod.gif

[Chris Kilroy]

Guys,

That's interesting, since we are not actually applying any compression to uploaded photos.

When a photo is uploaded, it is first resized to 200px wide, sharpened 10%, and saved as a thumbnail. The large photo is then reduced to 1024px if larger, an image of the same width of the original photo is created, the copyright added to that image, and the newly created copyright bar appended to the large image.

That's it.

I'm at a loss as to what could be causing a loss of quality.

[Chris Kilroy]

Here, by the way, is the code which does all this -- just so you guys know I'm not making it up. images/smiles/icon_biggrin.gif

[Bruce]

Chris,

It looks as if the images are re-sized to 1024x1024 and then sharpened 20. I think that may be the cause of it. If I sharpen an image 20% in photoshop, after its been optimized using USM etc then it will appear oversharpened, just a bit. The "compression" that I'm seeing may not be compression at all but rather a tad oversharpened.

I wonder, why is it important for your script to sharpen the image?

[Chris Kilroy]

Bruce,

The script resizes an image to 1024px and adds sharpening ONLY if the image was above 1024px when uploaded. The reason for the sharpening when an image is reduced in size is, as you know, an image reduced in size tends to become fuzzy.

When an image is uploaded at 1024px or smaller, as it should be, no sharpening or resizing takes place.

[Leftseat86]

:S note to self: upload in 1024 now images/smiles/icon_biggrin.gif

-Clovis

1024 only nod.gif

[cicadajet]

Chris, Whats odd is that of several images I uploaded recently, (ones that were a bit too aggressively sharpened on my end), they appear greatly degraded on JP from what they were when uploaded.. Mind you they were at 1024... But this is only when viewing through AOL. Checking on the same monitor, but not using AOL, they appear just as the original file did. Likely a problem with my own set-up, but thought I'd throw it out there in case there was a legitimate issue. Again, the difference is apparent in just a few cases that I've checked.

Tom

[Chris Kilroy]

Tom,

AOL's browser uses built-in image compression, which can severely degrade the quality of all images being viewed with the browser. IIRC, there is a way to turn that off.

[PolishAir42]

Or use Internet Explorer. Of course the best browser. images/smiles/icon_biggrin.gif

[Anonymous]

Hi all

My first image uploads, I have noticed some compression also, especially around titles and registrations.

Not sure what that can be.

Cheers

Gary Watt

[bfpires]

I don’t want to say anything stupid, but I really thought you guys at jetphotos were applying some kind of compression on any and every uploaded photo.
I mean, just in order to keep pictures lighter for everybody to see...
What about the dpi size?

[LX-A343]

Something happens to the pictures. I thought so far, it was the JPG compression. All I know is, that the filesizes of the Jetphotos pics are smaller, than the original filesizes (some 20% less in an average).

Gerardo

[lockon]

I thought the same thing when I uploaded stuff this weekend. I noticed excessive JPG compression around the red objects in the photos. The red bleeds into the other areas a little.

I’m looking at the code that Chris posted now…

<FONT COLOR="black" SIZE="1">[ January 28, 2003 03:31 PM: Message edited 1 time, lastly by Sunil ]</font>

[Anonymous]

Hi all

Pics I uploaded yesterday with no pre-compression have uploaded to the site with no problems.

Seems like I have to upload the processed image 'as is' without compression via JPEG Wizard or similar.

Cheers

Gary

[Bruce]

Gary, were yours 1024pixels wide?

I notice now that I re-size to 1024 wide that I dont get the compression-look.

[Anonymous]

Hi Bruce

No, I am uploading at 1000 pixels wide.

Latest few pics uploaded are OK so, to me anyway, it looks like pre-compression causes further compression.

I'll stick with uncompressed uploads in future.

Cheers

Gary

[lockon]

Bruce, I noticed the same... the 1024 wide uploads are fine but the 1280 uploads don't look as good as if I had resized them myself.

BTW, I downloaded ImageMagick and played around with it… cool utility! It seems there is a newer version (5.5.4 Q16) on the web than what this site uses because I could not get the script that Chris posted to run without some small changes to the arguments. Also, I resize the 1280 wide image of the F-14 I uploaded and it looks *much* better than the one that shows here (no running colors). Plus, I didn’t even need to apply any sharpening (note this Chris!).

[gbasco]

I’ve used Neat Image once in a while to clean some pics, but try to stay with PS. I always stick with 1024, but I do have a couple pics which are not so good and wondered if there will be a re-upload possibility?

TIA

[PolishAir42]

gbasco see http://www.jetphotos.net/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=000106

Chris should start working on it after the server move I hope

[gbasco]

Thanks, good news.

I guess it will go through screeners again.

[Chris Kilroy]

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by gbasco:
Thanks, good news.

I guess it will go through screeners again.<HR></BLOCKQUOTE>

That's right, but only to determine whether the corrected photo is indeed the same photo it's supposed to be correcting. images/smiles/icon_wink.gif