Image uploads and shows thumbnail - doesn't display in document

I have a new installation of MODx on the same host as another older installation. I have a configuration error that I have reported to the host:

Configuration warning: ’GD and/or Zip PHP extensions not found’

What does this mean?
MODx needs the GD and Zip extension enabled for PHP. While MODx will work without them, you will not be able to take full advantage of the built-in File Manager, Image Editor or Captcha for logins.

Although I can upload images and see them as thumbnails, when i select them to insert them into my document they do not show, do you think this could be due to said error ?

No. GD is mostly useful for generating thumbnails and CAPTCHA images, while the zip libraries are used for for unzipping .zip archives uploaded via the Manager’s file manager. Most PHP installations have GD, but many don’t have zip. You can see which you are lacking by checking the "view source" link for phpinfo in Reports -> System Info.

Your problem is an issue with the version of TinyMCE included with MODx 1.0.4 (and has been brought up in a previous post reporting this same failure). Do the images show up OK in the site, and just don’t show up in the resource editor?

Here is the difference in the HTML for the same image in TinyMCE in a 1.0.4 installation and in a 1.0.2 installation. Notice that Tiny MCE is mangling the basic image tag elements:

They show up in resource editor fine ! but when I select the image it doesn’t show in the preview box or on the website.

Finally got to the bottom of it.. The images folders permissions were set to 766, I changed it to 777 and it now shows up ok.