Going through multiple blogs/ forums for Constant Contact's very long running problem... They always give the same generic answers instead of optimizing/ updating their software to be able to render high resolution images. Maybe have simple revisions such as dimension notes, or specifically note/state that the Constant Contact software can't render a high-resolution Retina display image properly.
From what I gathered they still have not fixed this issue and it doesn't seem like they plan to considering how long they have allowed this issue to continue.
To get semi-good quality, 800px seems to be the best bet, but don't expect it to look crisp and defined, even with standard resolution images...
Thank you for reaching out to the Community about your images! We are still trying to troubleshoot this experience as it does not happen to all customers. Having some further details will allow us to know what updates need to be made. For instance, are your images a PNG or a JPG? If your image editor has an option to "Save for Web & Devices" or to "Optimize" the image, can you choose a resolution that shrinks the image's file size to less than 5MB?This is valuable information needed for our Product Team.
I'm sorry to hear you're having this experience as well. Which images do you see this happening with? I took a look at your account and can see you have uploaded both a JPG and PNG version of some of your images. We always suggest saving your images as a PNG to get the best quality.
I found this post because I'm also wondering why uploaded images into the CC library come out blurry. I only notice this now because I have an Apple Retina display. The only workaround I've found is to upload my images to imgur and then use the link image option. When I do that my email graphics look crisp.
It would be nice if Constant Contact didn't default compress images. Don't tell me you don't either because I've uploaded the exact same images to your library, and then imgur, and they look great in the email using imgur, but come out blurry/compressed looking when uploading to constant contact.
Your workaround could work quite well in many cases. We are very open about the fact that we do compress any images that are more than 800 pixels wide. If your original images are larger than that, there is a good chance that many computers and mobile phones may have some display issues, or delays in downloading the images. You're welcome to use an image URL instead, though we can not guarantee the speed at which the images will download for your recipients.
Thanks for the info Aaron, I didn't know that about the 800px wide compression. This new retina display is just taking me for a spin, because things that looked fine before now look blurry.