Image-based tools vs code-based tools
An image-based generator gives you a fixed PNG or JPG — fine for a one-off hero image, but it doesn't scale cleanly and can't be tweaked later without regenerating from scratch. A code-based generator like CoolBG produces CSS or SVG you can keep editing, resize infinitely, and drop straight into a stylesheet.
What to check before you commit to a background
Licensing — can you use it commercially without attribution? Export options — PNG only, or also SVG and raw CSS? Performance — does the background add page weight, or is it lightweight vector/CSS? Customization — can you match it to your brand colors, or are you stuck with presets?
Why procedural generation is worth it
Because every background on CoolBG is generated by an algorithm rather than pulled from a fixed image library, there are effectively unlimited variations, no two visitors need to see the same random background twice, and nothing is ever a stock photo someone else is also using on their site.