An image crawl is a nice way to display a selection of thumbnail images without resorting to a big table that takes up most of the page. Ideal for sites that have a lot of images, such as those offering photography or graphic design services, or for those where the appearance of the product is a major selling point, as with jewelry sites, these crawls are a simple way to add some animation and interactivity.

An image crawl basically works as follows: you have a selection of thumbnails (photographs you've shot, pieces of jewelry you're selling, etc) that go across the screen either vertically or horizontally. Those images move slowly across the screen, allowing a viewer to browse the images. Typically, the crawl will be set up with links, so that when the viewer clicks an image, it will go to a larger view of the photograph, the jewelry piece's purchase page, or the like.

These functions have their weaknesses, as well as options that can minimize and mitigate them. Generally, image crawls are made to move fairly slowly, making them poor choices for getting people to the product they need. Image crawls should not generally be used as a main store display. Rather, they are a supplemental display intended to give a look at the products offered or the website owner's photography, graphics, and other work, as well as the ability to go to the actual jewelry piece, photo, design, or other item that catches a user's eye. Since image crawls take up much less space than a typical catalog section, they are great for placing on every page of a site, keeping the products at the forefront of the visitor's attention.

Image crawls are also often made up of several images. This can result in a high loading time, even with tiny thumbnails. Using pre-sized thumbnail images is a must; not only will quality suffer drastically if you simply set the width and height properties of a full-size image to thumbnail size, but this will not actually reduce the size of the image being downloaded. Even then, you want to keep the number of images to a manageable size. You don't want the entirety of a large jewelry database to be appearing, for example. Good solutions are to choose specific featured images, or, if you want every image to potentially display, use a random selection from a database with a limit. This can be particularly effective if the images show up on different pages, giving a visitor a new selection each time they change the page. Other options include displaying only from a page-appropriate (or random) category. One final note regarding the difficulties of image number: if you have a lot of images in your crawl, and especially if your crawl appears on every page of the site, your "hits" will skyrocket. Moreso than ever, visitors should be your primary stat to look at if you want accurate statistics (or, as accurate as they get on the web).

Although those are the most notable weaknesses of image crawls, there are also some potential pitfalls that one should be aware of when creating them, and methods of coding that will minimize the impact of such problems. I discuss these in the next article on the details of image crawls.