For people wondering how to do it from scratch from Gt5:
(this is how I do it - does not require any hard transfer - all done through internet)
First, you take the photo in GT5, and save it obviously.
Then you go into your GT5 photo album, view the photo, & set the photo to "Share with friends", so it's online.
Then you can go to the Gran Turismo web site & sign into it with your PSN acct.
for example
https://us.gran-turismo.com/us/gt5/user/YOUR-PSN-NAME-HERE/
(I'm in the U.S. You can get to this just by going to
http://www.gran-turismo.com/)
On your GT5 user screen, on the left side is your photo album. Click on the photo.
On the bottom of the photo pop up there's a file/page icon like a little square. Click on that, and the photo itself will pop up in its own browser window/tab.
From there, right click (windows users), (or I believe it's ctrl + click for mac users?), on the image in the browser. And choose save.
Save it to a location that you're going to find it in of course!
Then you have to upload it somewhere. Like if you have an online photo album acct of some sort.
(Like link provided above :
https://www.gtplanet.net/forum/showthread.php?t=116825 )
OR, very nicely, GTP forum has a nifty little online photo album feature.
When you're on the forum, you click on your username in the box up on the top right of the forum content.
Then, when on your profile page, on the left side there's a link "Show Albums", click on that.
Add an album, and follow the instructions on how to upload your photo.
(You may need to RESIZE the photo before uploading. I have Photoshop, but I'm pretty sure most computers come with some sort of image editing programme that's capable of resizing pictures. Choose to resize by pixels, and just make sure the width is less than 800, and that the ratio is kept.)
Then, once you have a photo uploaded, click on the photo, and the page will give you under the photo, the URL for the photo which you can copy.
Copy that URL, and then you can use the image button at the top bar of the compose forum message window, to insert the photo into a forum post.
Or just use the "tags" described in one of the above posts.
Hope this helps, I'm probably not the best at describing this.
But it's a way you can do this all without having to use something to actually transfer the photo from your PS3's hard drive to your computer's hard drive, and without having anywhere online to put your photos - all you need is for your PS3 to be connected to the internet, and have a GTP account on the forum.