Interface Of Photopea Is Too Tiny
You have been using Photopea for a long time, but suddenly, all buttons, menus, text labels and the whole interface became too small and tiny (or too big), what is going on?
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Webpage Zoom
It is all caused by a webpage zoom. You told your web browser to scale the website down (or up). As a proof, you can see the magnifying glass icon next to "photopea.com"
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Fixing the problem
In Google Chrome, just click that icon and click "Reset", to reset the webpage zoom to 100%.
In Mozilla Firefox, just click the number with the value of zoom, to reset it back to 100%.
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How did it happen?
If you don't remember changing the webpage zoom, you probably did it accidentally by pressing some keyboard shortcuts. E.g. if you press Ctrl+Minus in Photopea, it zooms out the document. But if you click outside Photopea into the browser search bar, Ctrl+Minus is not delivered to Photopea, and a browser interprets it as zooming.