Hello.
If you can't figure out how to get a picture, you can try toribashtextures.com . Just upload the flats there and you can link a preview.
Also please read the market rules and add this info to your textures:
Originally Posted by Art Rules
C) Following information must be added to all textures and texture previews:
.....I) The resolution they are made and displayed in, from 128, 256 or 512
.....II) The original artist of the set. .....III) The previous owner of the set/texture when bought from someone else.
.....IV) Whether or not you are willing to recolour the items and how much it would cost.
If you have any more questions, PM me!