Garbled images when using Efax-gtk

[Andy K]

I am having problems with Efax-gtk.

I scanned some documents and saved them as png files.

I then used Gimp to convert them to pdf files.

When I used Efax to send them to faxtoy.net, the images are garbled.

If I send them using an online fax service, they are not garbled.

Is there any other linux fax programs? Preferable gui.

Thanks.