Saving photos without compromising quality

Welcome to the Apple Discussions.

Moving photos has no impact whatever on their quality.

Editing them does.

Your workflow could be simplified.

Normally I would copy all my holiday pictures onto my desktop directly from a card reader. Then I import the pictures to iphoto where I can edit them and delete the ones i don't want.

Why not import them directly to iPhoto? That saves a step.

Sometimes I export the photos back to my desktop (if I still want o do some work on them in photoshop,etc...

You can set Photoshop (or any image editor) as an external editor in iPhoto. (Preferences -> General -> Edit Photo: Choose from the Drop Down Menu.) This way, when you double click a pic to edit in iPhoto it will open automatically in Photoshop or your Image Editor, and when you save it it's sent back to iPhoto automatically. This is the only way that edits made in another application will be displayed in iPhoto.

Note that iPhoto sends a copy+ of the file to Photoshop, so when you save be sure to use the Save command, not Save As... If you use Save As then you're creating a new file and iPhoto has no way of knowing about this new file. iPhoto is preserving your original anyway.

... or I store them in my pictures folder.

Why store them in your Pictures Folder? Why not store them in iPhoto - it's what the app is for, after all.

What happens when I import photoshop edited photos back to my iphoto library?

Nothing. When you import you get a copy of the picture you're importing.

When you edit a jpeg there is an issue of generational loss because jpeg is a lossy format. What this means is that everytime you edit the pic and save it, some more data is lost.

To overcome this iPhoto has a _*[Non-Destructive Editing Feature|http://docs.info.apple.com/article.html?path=iPhoto/7.0/en/11464.html]_ *, so that you never go below more than a single generation.

Photoshop doesn't have this, but you do also have the Original in iPhoto and you can revert to it at any time.

Note: dropping a single generation or maybe two will not really impact the quality of the shot. It's when you start getting down to 6 or 7 generations that you see problems - depending on the quality of the original photo.

Regards

TD