We are having two related issues with using images in our VF pages for our products that we want to render to PDF (we are running in a Sandbox with Summer '08):
1) when we include an image file from an external server , the page will not render at all and gives an error 500. No PDF is generated at all. We have tried bringing the image in using both a normal <img> tag as well as the <apex:image > tags. We have tried being in and out of developer mode, and have tried https and http URLs to the external server that is hosting the image. The image does show in a browser window when we remove the 'renderAs=PDF'. We have tried images of various sizes from multiple external servers and the results are always the same - will show in browser window, will not even render the pdf file.
2) We also have an image at the top of the page which is a Static resource in SF. this image is essentially our logo header. When we choose render as pdf, (and remove any external image links), the PDF will be generated however the logo file does not appear. Again, it shows if we remove the renderAs PDF. As soon as we try to render as PDF, the image disappears.
Any ideas? is there any more information that I can provide??