Four words show up over and over when you go looking for website images: free, royalty-free, public domain, and CC0. People treat them as synonyms for "I can use this." They aren't. Each one answers a different question, and only some of them tell you whether an image is safe to put on your site.
This is a plain-English breakdown aimed at one decision: can I use this image on my website, and under what conditions? It's general information to help you understand the vocabulary, not legal advice. For anything specific to your project, check the actual terms of the image you're using and, if real money or risk is on the line, talk to a qualified professional. This post is one stop in the broader guide to using free and AI-generated images safely.
Why these four words trip everyone up
The trouble is that the four terms answer different questions but get used as if they answered the same one:
- Free is about cost. Did you pay money for it?
- Royalty-free is about how a paid license works. Do you owe a fee every time you use it, or just once?
- Public domain is about copyright status. Is the work still protected by copyright at all?
- CC0 is about a specific legal tool a creator can use to give up their rights.
Because all four can describe an image you didn't pay for, people collapse them into one idea. But an image can be free and still come with rules. An image can be royalty-free and still cost money. And most images that feel "free enough to grab" are not actually public domain. Getting these straight before you download anything is the whole point.
"Free" means no cost, not no conditions
"Free" tells you one thing: you didn't pay for it. That's all it tells you.
It says nothing about whether you can use the image commercially, whether you have to credit the source, whether you can edit it, or whether the person who uploaded it had the right to share it in the first place. Plenty of free images come with a license that limits what you can do, and a few "free" sources host images the uploader never actually owned.
So "free" is a price, not a permission. The permission lives in the license attached to that specific image. Before you use any free image, read its terms the same way you would read terms for one you paid for. We go deeper on this in are 'free' stock photo sites actually safe to use.
"Royalty-free" is a license model, not a free image
This is the term that catches the most people, because the word "free" is right there in it.
"Royalty-free" does not mean free of cost. It describes how you pay. A royalty is a recurring fee owed each time a work is used. With a royalty-free license, you pay (or qualify) once and then don't owe a per-use royalty after that. You can use the image many times without paying again each time.
Two things follow from that:
- A royalty-free image can still cost money up front. Many of the big paid stock libraries sell royalty-free licenses. You buy once; you don't pay per use.
- "Royalty-free" is not "no rules." There's still a license, and it can limit things like reselling the image on its own, certain sensitive uses, or claiming it as your own work.
So when a site says "royalty-free," read it as a payment model, not a giveaway. It might be paid, and it always has terms. For more short definitions like this, the visual-style glossary keeps a plain-English entry for each licensing term in one place.
"Public domain" and "CC0" are specific legal statuses you must confirm
These two are not loose descriptions you can assume from how an image looks or where you found it. They are specific legal statuses, and the safe move is to never assume an image has either one unless the source clearly states it.
Definitions in this section are general. For U.S. copyright basics, start with the U.S. Copyright Office's Circular 1; for CC0, use Creative Commons' public-domain guidance. Rights and duration can differ by country.
Public domain
Public domain generally refers to material that is not protected by copyright. That may be because protection expired, the material was never eligible, or a rights-holder used a valid dedication. The U.S. Copyright Office notes that some material is never protected, while duration and status can vary by work and jurisdiction. Old or widely shared does not automatically mean public domain; confirm the status at the source.
CC0
CC0 is a Creative Commons legal tool a rights-holder can apply to waive copyright and related rights as far as the law allows. It is a deliberate, labeled choice; you cannot infer CC0 from a free download.
The honest takeaway for both: do not assume an image is public domain or CC0 because someone called it "free," because it appeared on a free site, or because it's old. Confirm it at the source. If the source doesn't clearly state the status, treat the image as covered by a license with rules.
Side-by-side: what each term tells you about website use
Here's the same four terms framed around the decision you actually care about — putting an image on a site.
| Term | What it actually describes | Could it cost money? | Are there still rules? | What you must check before using it |
|---|---|---|---|---|
| Free | The price (you didn't pay) | No, it's free | Yes — the license still applies | Read the image's license: commercial use, attribution, edits |
| Royalty-free | A paid-license model (no per-use fee) | Yes, often paid up front | Yes — license terms apply | What the license allows and forbids; that you bought the right tier |
| Public domain | Copyright status (not protected) | No | Generally minimal, but status varies by country | That the source confirms public-domain status; it varies by jurisdiction |
| CC0 | A waiver tool a creator applied | No | Generally minimal once confirmed | That the source explicitly labels the image CC0 |
Notice the pattern in the last column: every one of these still requires you to check something at the source. None of them is a blanket "use anywhere, no questions." The label is a starting point, not the final answer.
How Picdrome describes its own terms
Picdrome doesn't use any of these four labels for its images, on purpose. Here's the wording we use instead:
Picdrome images are AI-generated. They are free to use for personal and commercial website projects, subject to the Picdrome license terms.
We deliberately avoid calling them "public domain," "CC0," "royalty-free," or "unrestricted." Each of those terms means something specific, and none of them would be accurate:
- The images are not public domain or CC0 — those are specific copyright statuses, and our images stay covered by the Picdrome license rather than being released with no conditions.
- They are not "royalty-free" in the paid-license sense — that term comes from a paid model, and you don't buy a license here at all.
So rather than borrow a label that doesn't fit, we say plainly what is true: free to use for personal and commercial website projects, subject to the Picdrome license terms. The terms allow real website work — homepages, landing pages, blogs, client sites, edits and overlays — while ruling out things like reselling the images as a competing library or claiming them as your own photography. The full, current rules live on the Picdrome Image License.
This is also why we don't tell you "you never need to credit." Whether a credit is required depends on the license, and that's true everywhere, not just here — the rule is read the terms per source. We cover that in do you have to credit free images.
In Plain English
These four words answer four different questions. "Free" is about cost (you didn't pay). "Royalty-free" is about a paid-license model (you pay once, not per use) — it can still cost money and always has rules. "Public domain" and "CC0" are specific copyright statuses you must confirm at the source, never assume. This breakdown helps anyone choosing images for a business website understand what each term permits before downloading. Reach for it the moment a stock site's license confuses you. Your next step: don't trust the label alone — open the actual terms for the image you want and check whether commercial use, edits, and attribution are covered. To see what one clear set of terms looks like, read the Picdrome Image License, and keep the visual-style glossary handy for more plain-English definitions. This is general information, not legal advice; for specifics, check the source terms and a qualified professional.
Common Questions
Does "royalty-free" mean the image is free?
No. "Royalty-free" describes a payment model — you don't owe a fee each time you use the image — but it can still cost money up front, and it always comes with a license and rules. "Free" only means no cost. They're separate ideas.
Is a free image the same as public domain?
No. "Free" describes cost; "public domain" describes copyright status. Most free images are not public domain — they're free to use under a license with conditions. Only treat an image as public domain if the source clearly states it.
How do I know if an image is actually CC0?
The source has to say so. CC0 is a tool a creator deliberately applies and labels; you can't infer it from the fact that an image was free or easy to download. If the source doesn't explicitly mark it CC0, treat it as licensed with rules.
Are Picdrome images public domain, CC0, or royalty-free?
No. Picdrome images are AI-generated and free to use for personal and commercial website projects, subject to the Picdrome license terms. They aren't released as public domain or CC0, and "royalty-free" doesn't apply because there's no paid license to buy. See the Picdrome Image License for the full terms.
For the bigger picture on choosing and using free and AI-generated images without guessing about your legal footing, start with the pillar guide to using free and AI-generated images safely.