Thumbnail Sharpness

The thumbnail images being generated are blurry, I can't seem to find where to set the JPEG quality of the thumbnails. I have tried this both as a JPG and PNG, with and without the watermark and got the same results.

Thanks

I wanted to report back on this. I was able to get better much better results by using PNG's only. PNG's are lossless, so the compression level does not affect the quality.

I scaled my images in PhotoShop to the exact pixel size as I am using for my full size images, so they do not get resized even when the watermark is added. (I verified this by bringing the images back into photoshop to compare to the original)

The Thumbnails DO loose sharpness compared to the same image resized in PhotoShop. I mitigated this somewhat by cropping in closer, and over-sharpening the original before import. This is due to limitations in GD, the resizing module that is default in PHP. This is a known issue that I found numerous references to. There is a better PHP module called ImageMagik, that also offers Sharpening options (at the cost of larger file size). I have used gallery components that give you a choice which method to use, that would be a good edition in the future.

Apologies for jumping in on this thread but I wondered if anyone has tried this technique to sharpen thumbnails using the GD library:
http://adamhopkinson.co.uk/blog/2010/08/26/sharpen-an-image-using-php-and-gd/
If it works it might be a useful option to add in a future release.

regards
Trevor