Stock photography: what’s available free and for a fee?

My article on using stock images to liven up your content marketing included references to a few stock libraries. These are sites where you can find images to use, either free of charge or for a small fee. There are pros and cons for each, although generally I’d suggest you limit free images to general blog posts.
I will review and extend this list as I come across more. Being included on it does not imply a recommendation.
Free Stock Libraries
Flickr
Flickr’s been around a long time and been through various incarnations. It has an extensive selection of photographs, although most are not available to use. To find ones you can use, search with the “Creative Commons” filters enabled. Quality is highly variable, primarily because it started as a personal photo-sharing site (think Instagram before it was created).
Pexels
A free to use stock library where everything is free to use and modify (with some restrictions). The quality appears quite high and varied styles are available.
Unsplash
Unsplash is a free to download stock library with a wide range of available images. All of the images can be downloaded, modified and used for commercial purposes. However, when I have found images that are used widely, they usually trace back to Unsplash. If you want something a bit less common you may be better looking elsewhere.
Paid Stock Libraries
500px
Chinese owned photo sharing website. You can find free to use images here if you look hard enough, although the search function doesn’t make this easy. Images which need paid licences link off to other sites. Although interesting, I don’t find it particularly useful.
Adobe Stock
Building off of their creator’s network, Adobe Stock offers a wide range of photographic styles and content. It uses a subscription licence, around £20 a month where up to 10 “standard assets” can be downloaded. Unused assets can be rolled over each month up to a maximum of 120 over 12 months.

Death to Stock
An artist owned co-op which has some quirky and left field imagery on site. The quality is consistently high and has character and personality. Subscriptions start at $12 a month with unlimited downloads. They sometimes release limited numbers of free to use images.
Getty
Comprehensive and long-standing stock library service. Quality is exceptionally high with a price to match. It’s particularly useful if you need time sensitive images around current events, or images of celebrities and personalities. Images can be bought individually and start at £150 for a small size, to over £3,000 for a pack of 10 high resolution images. It could be too expensive for a small business, unless you want to make an impact.
Shutterstock
Long established stock library that has a reputation for quality imagery at a reasonable price. Prices vary from monthly subscriptions to pre-paid packs to one-off images. Not all uses are covered by their licences, so you may need to check before you make your first purchase.
Which ones do I use?
There are 3 libraries that I tend to use. Flickr is where I’ve sourced images from time to time purely for blog posts. Occasionally I post Creative Commons images there too. Death to Stock and Getty are both sites where I’ve found images for commercial use.
Google Image Search
Just a friendly reminder that Google’s image search is not a place to source images. If you download something from there and put it on your blog expect an invoice or court summons.