showrooms often receive line-sheets in Adobe Acrobat PDF format. Personalized Bulk Email (PBE) feature accepts image formats (e.g., JPG) only. There are many free resources that can help with the conversion to JPEG.
here is one example:
http://www.pictureresize.org/online-images-converter.html
ref: http://www.makeuseof.com/tag/6-ways-to-convert-a-pdf-file-to-a-jpg-image/