What happens to your image
Nothing. It never leaves the tab you opened. This page explains how that works and what the tool does store.
The short version
Thumbnail Factory has no server to upload anything to. The whole tool is one HTML file served as a static page. When you choose a picture, the browser reads it off your own disk and draws it onto a canvas in the page. The finished thumbnail is produced by that same canvas and handed straight to your downloads folder. At no point does the image travel anywhere.
There is no account, no sign-in, no analytics script, and no tracking pixel.
How to check, rather than take my word for it
Open your browser's developer tools, switch to the Network tab, and use the tool normally. Choose a picture, type a headline, download the result. You will see requests for the page itself and for the font, and nothing else. No request carries your image, because no such request is ever made.
You can also disconnect from the internet after the page loads. Everything keeps working, which is only possible because the work happens on your device.
What is stored, and where
The tool remembers a few things between visits so you do not have to set them up
again. They are kept in localStorage, which is a store your browser
keeps on your own machine, scoped to this site. It is not sent anywhere, and it is
not readable by other sites.
- The two lines of headline text
- The size you last picked, and any custom width and height
- Your headline colours
- A logo you uploaded, if you replaced the default one
The picture you are working on is not stored. It lives in memory while the tab is open and is gone when you close it.
To clear everything, clear this site's data in your browser settings, or use a private window, where nothing is kept once you close it.
What the page does load from elsewhere
One stylesheet, from Google Fonts, for the typeface the headlines are set in. That request tells Google the font was requested from this site, in the ordinary way any web font does. It carries nothing about your image or your text. If you would rather avoid it, the page still works with that request blocked; the headline simply falls back to a system typeface.
Why it is built this way
Most free thumbnail tools upload your picture to process it. That is a reasonable engineering choice and it is also how you end up agreeing to terms about what may be done with what you uploaded. Drawing on a canvas in the browser avoids the question entirely. There is no copy of your work to keep, so there is no policy needed about keeping it.