Online stock image agencies are a great resource for designers when creating large format signage, advertisements, and displays. Getting the right image can be as easy as the click of a button. Finding an image that is appropriate for large format output can be more challenging.
There are several sites that have ‘large’ or even ‘xx-large’ files. Corbis offers high-resolution files at a premium. Getty Images, a giant in the stock photo industry, also has several subsidiary companies that are narrowed down into specific genres. WireImage focuses on music, celebrity, and fashion photography, while Contour specializing in the licensing and syndication of high-end celebrity portraiture. iStockphoto, also a subsidiary of Getty, has gained enormous popularity by supplying a variety of subject matter and file sizes Each site has their own pay structure, depending on file size and usage, via either photo credits or subscriptions.
The most important thing to keep in mind when searching for images for large format use are the file size or pixel ratio of the file. Depending on the final output size, even if you are purchasing the largest version of the file, it still may need to run through Genuine Fractals or similar resizing software to get the best result. A great alternative, if your design allows, is to use vector files because they can be transformed into whatever size you would like without any image loss. Most sites allow you to specify the type of file you are looking for in the search options.
There are many more websites that offer Royalty Free or Rights Managed stock imagery for your design needs. Blue Vertigo has a very comprehensive list of sites broken down into category by use and price, as well as other great references for designers.
With the myriad of sites available, easy search features, and payment options, finding the right image for your large format design became a little less challenging.