Pixelated images in safari, can this be fixed?

[bonustokin]

Hi everyone,
Glad to be part of the forum. Hoping someone can help me with a issue i have with my new macbook pro.
When browsing the net, safari and firefox show really pixelated images. I thought it might be my internet connection compressing data or something, but i have tried other computers on the connection and the images show perfect...
So this makes me think its the macbook. I have upgraded snow leopard from 10.6 to 10.6.2 and updated safari, but unfortunately this didnt help my problem. So now i have ended up here, asking you people, coz im out of ideas.
I will include some screen shots so you can see exactly what i mean.
Notice the bad images and even on google's banner it is pixelated heaps...
Please help if you can. Its very annoying. Cheers.

 

[Tumbleweed666]

Doesn't look pixellated to me

What do other jpegs look like on your macbook? Are they fine or also pixellated? What happens if you save an image from safari or firefox to disk and then view it in Preview? The same or OK?

I wonder if you have a less than optimum resolution set on your macbook?

 

[BlueRevolution]

It's not pixelated, it's using extremely high JPEG compression. And yes, I do find it painful to look at too. Do you or your ISP use any sort of internet "accelerator"?

 

[bonustokin]

Tumbleweed.
Jpegs from my digital camera and stuff look fine, but if i right click on a image in safari and 'save image as' the picture shows the same in preview
Res is set to the highest i have available, which is 1280x800.

BlueRevolution.
Thanks for confirming.
Its definitely not an accelerator, because i dont use one, and if i use the same internet connection on another computer, the images show perfect on that other computer. It has got to be this macbook...

Please keep suggestions coming.
Cheers

 

[BlueRevolution]

It must be something you've installed on this computer then, maybe something you've forgotten about. Take a look through System Preferences "Other" section, as well as through /Applications, for anything that might tinker with your internet connection in any way.

I don't know of any Mac apps that would do this, but obviously there is one.

 

[bonustokin]

BlueRev
I havent installed anything apart from firefox and Adium. In 'other' the only app is Growl, that comes with Adium.
And in Applications is just stock apps with firefox and adium.

Ive spent time on the phone today with apple tech support, setting up new user accounts, changing the location of the network and manually removing plugins. Nothing worked, and i had things to attend to, so i had to leave it at that.

Ive been browsing the internet today and just realised there are a few websites that i dont have this problem with... But its only a few, the majority show poor quality.

If you have any ideas, please let me know.

 

[Makosuke]

There is absolutely no question--what you're seeing is the image recompressed at a very high compression ratio. That's exactly what it looks like, and I tested to make sure by saving the image of that snake off the site and running it through GraphicConverter; at 13% compression the compression artifacts are identical, so that's exactly what's happening here.

The only question is what's doing it. Nothing I'm aware of will recompress an image on the fly for Safari--there's no logical reason to do that. Which only leaves something attempting to accelerate downloads of images, as BlueRevolution suggested--many "internet accelerator" systems do exactly this.

If you definitely haven't installed anything, and other computers on the same internet connection aren't doing it, then the only thing left is a proxy setting (or maybe manual DNS override, but I've never seen an accelerator that works that way).

Go to System Prefs --> Network, and select either Ethernet or AirPort from the list, whichever your internet connection is using. Click the "Advanced" button at bottom right, and select the "Proxies" tab. Do any of the options in the list have a checkmark beside them?

I have to think that's it, but if nothing there is checked, then you're still getting the images intercepted somewhere between the original server and your computer and having them recompressed. Who's your ISP, and what router/connection type are you using to connect to the Internet?

 

[bonustokin]

Makosuke
Thanks for the reply.
Nothing is ticked in Proxies, except for 'Use Passive FTP Mode (PASV)'

Im with OPTUS and im using iphone internet tethering for connection on the macbook.

 

[Makosuke]

Ok, that explains it. Apparently Optus routes at least some tethered internet traffic through a "transparent" accelerator proxy, meaning you're getting a proxied connection whether you like it or not:

http://forums.whirlpool.net.au/forum-replies-archive.cfm/1240106.html

If you do a bit of Googling you'll find plenty of people complaining about it, and it's apparently inconsistent, so that might explain why you sometimes see it and other times don't. They presumably did this to reduce load on their wireless network.

I have no idea why other computers using the same connection wouldn't see it (you sure they don't see the same recompression on the same images?), but short of figuring out how to get Optus to turn it off there's not much you can do. Who knows, maybe there's a setting in your online account, or you might try asking tech support.

A workaround would be to use an encrypted proxy, so Optus never actually sees the raw traffic, but that's probably going to be relatively expensive, and likely isn't worth it.

Sorry there's no easy fix.

 

[bonustokin]

Well thanks for clearing that up for me dude.
Like i said though, when i try it on other computers they show the same webpages perfect. So i dunno whats going on with that.
I will try a wifi connection somewhere and see if it makes any difference.
Thanks again.

Update: Just tested the iphone tethering on yet another computer and it works fine... Could it be a issue with optus on macbooks? All the other computers im trying it on are windows machines and they display all the webpages perfect...

 

[Makosuke]

Not knowing exactly how their proxies are set up, I can't say why other machines wouldn't be behaving the same. Could even be coincidence, unless the behavior is different when you access a site from two computers one immediately after the other.

One possibility is caching; if you accessed the website on a regular internet connection (or didn't get the proxied version for whatever reason), then the browser on that computer would have a cached version of the proper image, and as long as it doesn't reload the image will continue displaying it even when on the proxied connection. You could test this by either going to the same page with another browser on that computer that's never been there before, or just hitting "reload" to see what happens when it downloads a fresh copy of the image.

The other thing I can think of is that the proxies only respond to certain kinds of queries, and aren't kicking in on whatever browser the other computer is using, but that seems like a long shot.

Regardless, it can't be anything Mac specific unless Optus is changing caching settings based on the ID string of the browser, which would just be bizarre. You can test that by turning on the Develop menu in Safari and changing the User Agent to another browser and/or Windows, to see if anything changes.