Online Batch Image Darken Tool

What Online Batch Image Darken Tool actually does

Batch proportional darkening for up to 30 selected images. One shared Adjustment strength (%) numeric setting applies to every file; it defaults to 25 and processing clamps it to -100..100. Positive values darken, zero is neutral, and negative values brighten proportionally.

Checkable example

Verified pixels: RGB(100,160,240) at amount 25 becomes RGB(75,120,180); at 100 it becomes black RGB(0,0,0). At -20 it becomes approximately RGB(120,192,255), clipping blue; inputs beyond -100 or 100 are capped before multiplication.

Controls, output and limits

Every RGB channel is multiplied by 1-amount/100, then clamped and byte-rounded to 0..255. Alpha and dimensions remain unchanged. This preserves channel ratios until clipping and differs from the separate brightness tool's fixed offset.

Worked batch use: load consistently overbright catalog images, choose 25 and Generate. Every image receives a 0.75 channel multiplier, but originally darker files can become too dim. Inspect each preview and retain the originals rather than assuming a shared batch value is universally suitable.

Each input must have an image MIME type, be at most 25 MB and decode to at most 24,000,000 pixels. The selected batch is capped at 100 MB and 40,000,000 decoded pixels; selecting more than 30 files rejects the whole selection.

Every result is encoded as PNG and named from its source base name plus -darken.png. Download all starts separate downloads about 180 ms apart; it does not make a ZIP, preserve the input format or offer an output-format selector.

Processing is local in the browser and Generate must be pressed after settings change. This is a global decoded-RGB multiplier, not camera exposure metadata editing, RAW highlight recovery, an automatic enhancer or a region mask. Clipped or blacked-out detail cannot be restored from the exported copy, so keep the source files.