Sometimes Firefox can come up with a warning asking you whether to load images from a particular site. If you select to block the images the sites will be added to a blocked list in your Firefox settings so that instead of seeing the images you will see a white box with a red 'x'.
To check whether this is what has happened go to the Firefox Tools menu, then Options. Select Content, and ensure that the "Load images automatically' option has been selected.
You will also need to click on the exceptions button to the right to see whether Firefox should be displaying images from iDashboard and from your website. If you see iDashboard in the list of blocked sites you can click on the name to highlight the site, then click Remove Site. You can also click the Remove all Sites button to allow images to be displayed from all websites that you visit.