Best way to deal with image thumbnails on news web site (CMS)?

[eluser]Markc[/eluser]
Hmmmm, for now I implemented this solution. As I said I'm using Grocery CRUD, so I'm generating thumbnails after the upload using Image_moo library.

Code:

$this->image_moo->load($file_uploaded)->set_jpeg_quality(90)
            ->resize(350,210)->save($new1,true)
            ->resize(280,168)->save($new2,true)
            ->resize(196,118)->save($new3,true)
            ->resize(120,72)->save($new4,true)
            ->resize(100,60)->save($new5,true);

What do you think about Image_moo library? Is there any better library? The jpeg images are ok, but the size od png images is not really reduced.

P.S. This solution is ok for now as it wouldn't spend CPU/RAM at all because they will be stored on the file system. But the question is, would the server became slower because of the big number of files? I divided them in different folders, but I don't know if the system will become slow if there are let's say 10.000 images in one folder and the image have to be loaded from that specific folder?