I had to "customize" a newsletter for a client that required me to insert images into the newsletter using HTML:
<img width="110" height="92" border="0" align="left" src="http://www.website.com//nletter_images/3.jpg" alt="Inline Image" />
I did a test with Litmus and everything showed up just fine. I also ran the Litmus SPAM test and the only two items failing were the HTML validation and Outlook (Failed with a score of 8.0), which they set the spam filter to high.
Is it "legal" to code the newsletter so it's adding images from my client's site or does this cause a SPAM issue..
Thanks in advance
Referencing images in that way is perfectly standard and is not on it's own a significant trigger for spam filtering. The content, and the balance of images to text are far more important.
Campaign Monitor references all images from our own system unless you specific otherwise, so we can confirm that it doesn't cause problems in general.
Google may not place your email in spam but it may not load images. At least all the emails I get are without images with an option to "load images from this email".