Online Batch Image Sharpening Tool
Batch process multiple images: enhance image edges and local details. Processing takes place locally in your browser.
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What Online Batch Image Sharpening Tool actually does
The tool accepts at most 30 browser-decodable images by multiple file selection or drag and drop. It enforces 25 MiB and 24,000,000 decoded pixels per file, plus 100 MiB and 40,000,000 decoded pixels for the batch.
Checkable example
At 0% the original is retained; at 100% the full kernel result is used. Sharpening can amplify noise, halos and clipping and cannot recover detail absent from the source. The two masks are not an AI restoration model or an unsharp-mask radius control.
Controls, output and limits
Controls are convolution mask size 3 by 3 or 5 by 5, with 3 by 3 selected initially, and Strength from 0% to 100% with a default of 25%. Generate image reruns the chosen kernel for all loaded files.
The 3 by 3 kernel is [0,-1,0; -1,5,-1; 0,-1,0]. The 5 by 5 kernel uses center weight 17 with surrounding -1 and -2 weights. The filtered RGB values are blended with the originals by strength/100; alpha is preserved.
Outputs keep source dimensions and download separately as PNG files ending in -sharpen.png. There is no ZIP, format selector, metadata preservation or animation preservation; processing is browser-local.
The convolution result is first clipped to 0–255 and rounded to an 8-bit value, then blended with the source and rounded again. For a 3×3 mask with a center channel of 100 and its four direct neighbors at 0, the convolution is 500, clipped to 255; at 50% strength the final channel is 178, not 255.
Processing runs in strips. Changing strength or mask size cancels the current run and clears its previews and downloads; press Generate image to start again. Clearing or loading new files also cancels old work.
Review every preview, then click Download all. It starts separate PNG downloads about 180 ms apart; there is no ZIP or per-image download button.
Per image: ≤25 MiB and ≤24,000,000 pixels. Per batch: ≤100 MiB and ≤40,000,000 pixels. Selecting over 30 files or any invalid image rejects the whole batch.
Processing takes place locally in your browser.