image files and PDFs

[shroomer]

is there a correct way to publish PDFs so that image files look good when viewed on screen? for example i have created some sketch style elevations that are saved as images (no colour so i tried GIF and JPEG) but when i open the PDF the lines are never clean and crisp. only if i zoom to within a very specific range it looks OK, but never as good as the original file.

 

if i use an image viewer (e.g.Irfanview) to view the original image, I can zoom out as needed and the image always looks ok.

 

any ideas?