Image formats and watermarking

sigplus can process the lossy image format JPEG, as well as the lossless image formats GIF and PNG, both with index and alpha channel transparency. For all image formats, sigplus supports watermarking.

The two sample galleries below illustrate how alpha channel transparency is properly handled in sigplus when generating preview images. Compare how both images blend nicely into the background let it be white or cyan.

A sample watermark image with alpha channel transparency sigplus supports watermarking. A watermark is a PNG file with transparency channel (i.e. the image has RGBA color scheme) placed either in the same folder where the images to be shown are (specified within the plug-in activation start and end tags), or in the image base folder (specified in the administration back-end). Consider the following example that applies a checkerboard watermark (see right) to each image in a folder. The watermark is placed in the bottom right (southeast) corner, 10 pixels from the right edge and 40 pixels from the bottom edge:

{gallery watermark=1 watermark:position=se watermark:x=10 watermark:y=40}sigplus/sonnabend{/gallery}