How to configure the site-wide quality of thumbnails and previews.
This is configured under Settings - Behavior - Renditions in the FotoWeb site settings.
Thumbnail and preview quality
On these pages you can control the quality of the thumbnails and previews that FotoWeb generate.
All asset representations smaller than up to 200 pixels in size are rendered using the Thumbnail settings on this page. Representations above 200 pixels in size are rendered using the Preview settings. This means that if you configure your site to use thumbnails larger than 200 pixels in size, the Previews settings will control how they're rendered.
Quality: This setting controls the JPEG quality (the compression factor). The valid range is 0 – 100, where 100 is the best (lossless compression). This setting will have a great impact on the size of the generated images. The recommended default value is 80 and will result in images that are of relatively good quality and quite fast to download. If thumbnail quality is very important, you may want to increase this value.
If you increase this value you will see quality improvements that can be quite visible on some types of images. However, you will also increase the size of the images. This will have an effect on system performance, as browsers will need more time to download the images, and it will result in greater network traffic. Also, because of the increased size of each item, there will be space for fewer files in the FotoWeb caches.
What's affected by the quality settings?
Site-wide the thumbnail and preview quality settings affect:
- Thumbnails and previews in the main and Pro web interfaces
- Poster images and key frames for video files
- Previews shown when doing picture conferencing using FotoWeb Screens
- Previews used for the image Crop module in FotoWeb Desktop
Increasing quality with sharpening
FotoWeb will apply an unsharp mask filter to the images if this option is selected. This can drastically enhance the quality of your thumbnails and previews. Normally, you will use a stronger filter on thumbnails than previews.
If you change the unsharp mask settings you will only see the effects on images that are not already in the cache. To regenerate all images, restart Microsoft Internet Information Services and clear the content of the site’s cache folder.
Set defaults: The Set Defaults button resets the options for the unsharp mask to the suggested values.
After changing the quality settings the FotoWeb cache must be cleared for the changes to take effect.