Where can I find affordable stock images for industrial, maritime, and technology themes?

For a limited budget, microstock libraries are a good place to start. Community recommendations included Bigstockphoto, Fotolia, Dreamstime, and Shutterstock, which typically offer broad commercial stock collections and are likely to cover industrial, maritime, and technology subjects.

If your budget is especially tight, it can also be worth searching Creative Commons images on Flickr. Just be careful to verify the exact license and whether commercial use, modification, and attribution requirements fit your website and brochure use.

If you need more technical or scientific subject matter, a science/technology-focused image collection may also help, especially for conceptual topics like measurement or communications.

In short: start with major microstock sites for convenience and variety, then check Creative Commons sources if you need lower-cost options and can manage the licensing details.