Layer opacity is supported only in .pxm and .psd file formats.
Transparent images are supported only in .psd, .pxm, .png, .tiff and .jp2.

100% Opacity

50% Opacity

10% Opacity
To specify opacity for a layer:
- Select a layer in the Layers palette.
- In the Layers palette, click and drag the Opacity slider to change the layer opacity.