Take compression quality into account when manually cropping images

When manually cropping JPEG images in the UI, it can happen that resulting images are larger than the originally uploaded images.

The reason is that in the UI, any set compression quality (see "4. Configure the gallery processor" at 1) is not taken into account.

Code wise, in org.hippoecm.frontend.plugins.gallery.editor.ImageCropEditorDialog, it should be easy enough to expose the compressionQuality from the gallery processor and to add it as extra parameter:
ImageUtils.writeImage(writer, thumbnail, compressionQuality)

[1] http://www.onehippo.org/library/concepts/images-and-assets/create-a-custom-image-set.html