Images/Pop-Ups

Images can be used in a variety of ways in online surveys:

images can be shown on a screen by themselves or with questions beneath
small images (aka "thumbnails") can be presented as the response options to a survey question, and when clicked a larger version of the image can appear ("pop-up")
images can be shown side by side for comparison
images can be included in complex exercises including discrete choice, max diff, etc...

Critical Mix will use a programming technique called "floating divs" to pop-up larger versions of images which cannot be defeated by pop-up blockers.

All images to be presented in an online survey should meet the following requirements:

.gif or .jpg image files
72 dpi
The widest an image should ever be is 1000 pixels, in order to avoid horizontal scrolling to see the entire image - and this is for displaying on a screen by itself, separate from any question
If multiple images are to be displayed side-by-side on a screen, then the combined width of those images should also be no greater than 1000 pixels
Image height is generally less important since a little bit of vertical scrolling is usually okay, but height should be 500 pixels or less if you want an entire image to display with no vertical scrolling
If images are to be included in a question, with select-boxes or rating scales next to them, images should be about 125x125 pixels (width x height) max, and the image tiles should include any text or additional info that you want to display with the images - i.e. that info should be part of the image
In discrete choice store-shelf exercises, images may be up to 175x175 or 200x200 depending on how many are shown on a screen at a time

Critical Mix generally implements a variety of image security measures to prevent image copying/printing. But it is important to understand that nothing works 100%, since anyone can take a digital picture of a computer screen and email it around. Measures include:

Images are stored in a database on the web server so that they are not "cached" when displayed on respondent computers
Ability to right-click on an image to save/print it is disabled
Internet Explorer's "image toolbar" is disabled
Printing of survey screens results in blank page
Survey screen constantly clears Windows clipboard to prevent copying and pasting while in the survey
When linking back to review a previously displayed image, we do so in such a way that avoids pop-up blockers and does not show a browser address bar
When a study is closed, image access is denied