What it is
The Image Filters tool applies visual adjustments to a picture in the browser: brightness, contrast, saturation, blur, grayscale, sepia and inversion, with the result updating as you move each slider.
What each control actually does
Knowing this saves a lot of random dragging.
- Brightness lifts or lowers everything at once. Too much and the bright areas go flat white with nothing left in them.
- Contrast pushes light and dark further apart. It is what makes a flat photo look crisp, and what destroys detail in shadows when overdone.
- Saturation controls how intense the colours are. Zero saturation is grayscale.
- Blur softens. Useful for a background, and for hiding something you do not want readable.
- Grayscale and sepia are stylistic; sepia is the warm tone that reads as old photograph.
- Invert swaps every colour for its opposite, which is mainly useful for reading a negative.
Working order
Adjust exposure before colour: brightness and contrast first, saturation afterwards. Colour choices made on a badly exposed image usually have to be redone once the exposure is right.
Small moves compound. Three subtle adjustments almost always look better than one large one, and the difference between an edited photo and an obviously edited photo is usually just the amount.
Nothing is uploaded
The whole operation runs inside your browser. Your file is never sent to a server, never stored and never seen by anyone else. There is no queue, no daily cap and no account: the only real limit is your own device.