Concretely, the HEIC is decoded, the mark is composited and the result is re-encoded, so the watermark is baked into the pixels rather than living in metadata anyone can strip. You control the position, the size and the opacity, and the same settings are applied consistently across everything you upload.
Can I use my own logo, or only text?
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Either. Upload a transparent PNG logo, or type text and choose the font, colour and opacity. A tiled repeat is available when one corner mark is too easy to crop away.
Does the file format affect how the watermark comes out?
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It does. this format is read and written by the same streaming pipeline as everything else we support. That governs how cleanly a semi-transparent mark can be blended into the underlying content.
Anything specific to HEIC worth knowing?
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Yes — HEIC decoding needs the HEVC licence stack that Windows and most browsers ship without, which is usually the real reason the file is here at all. It affects when in your workflow the mark should be applied.
Does a watermark actually protect my work?
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It deters casual reuse and it credits you; it is not security. A corner mark can be cropped and a faint one can be painted out. If protection matters, a large semi-transparent mark across the subject is far harder to remove than a discreet one in a corner.
Should I watermark before or after resizing?
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After. Watermark the final deliverable at its final size, so the mark stays legible and proportionate. Watermarking a master you will process again means the mark gets resampled and compressed along with everything else.
