image texture not showing in yafray

Hello,
I have a material with several texture layers, one of them an image texture (with alpha channel). If I render with blender everything shows up as intended, but if I render with yafray, the image texture is not showing!? Do I have to change a setting for yafray?

It’s most likely the wrong image format…it’s question #1 in the FAQ at yafray.org

http://wiki.yafray.org/bin/view.pl/UserDoc/FaqEng#Q01_Why_do_my_textures_not_work

thanks very much for that link! Actually I used png, which is not supported!