Concretely, the filter is applied to every frame with a single shared palette derived afterwards, which keeps colours stable across the animation instead of shifting frame to frame. You pick the effect and its strength and the transform is applied to the whole file at once.
Which effects are available?
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Grayscale, sepia, invert, blur, sharpen, and brightness, contrast and saturation adjustment. They can be combined, and combining them in one pass is better than running the tool repeatedly.
Does the source format change how a filter looks?
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It can. GIF is capped at a 256-colour palette with single-bit (on/off) transparency and no partial alpha, which is why photographs band and dither in it. Colour depth and the palette model in particular decide how smoothly a gradient or a blur can be represented.
Anything specific to GIF to keep in mind?
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Yes — the palette is shared across the whole animation, so any change to one frame is negotiated against the colours every other frame needs. That is often the difference between an effect looking clean and looking banded.
Can I undo a filter after downloading?
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No — the effect is baked into the output pixels, which is the point of applying it. Keep the original file; that is your undo. Grayscale and blur in particular discard information that genuinely cannot be recovered.
Can I apply the same look to a whole set?
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Yes. One filter configuration is applied across the batch, which is how you get a visually consistent gallery rather than a set of individually-tweaked images that almost match.
