I agree with jsalab and will re-state what I see as the problem. Coppermine allows the administrator to set the maximum dimensions of an image. In my case this is the maximum size of the intermediate image. An image uploaded which is bigger than this gets re-sized by the GD library routines. The resizing gives a poor quality result. A sharp image ends up being quite fuzzy after re-sizing and some of the users of my gallery complained about the results. It’s not practical to increase the maximum dimension settings because then the pages are too large to fit on the screens of some users without a lot of scrolling (I had complaints about that as well). I don’t know enough about the GD library to know if there are settings that will give a better result – for example a setting using the sinc or lanczos resizing algorithm. There is a good explanation of this area on the excellent
Cambridge in Colour site. As far as I can see my web host does not have Imagemagick available so unfortunately that isn’t an option, although I would be interested to know what it is capable of doing. While I realise that USM is available to sharpen an image I’d prefer not to do that due to potential problems with halo edges and want to rely on a decent resizing algorithm.
To sum up, I’m looking for either:
- resizing that gives a better quality image than the GD method currently in use
- or, a way of rejecting an image during upload if it is bigger than the dimensions set by the administrator so that resizing is avoided
Am running CPG 1.5.12.