Free image editor: resize, crop and convert your photo

English uses the words "image size" for two different things: how much the file weighs and how many pixels it holds. This page always means the second one, and the editor works the same way. A pixel is the smallest element of a digital image, a single point of one colour[1].

An image described as 1080 × 1350 px holds 1080 points across and 1350 down. Together that comes to 1,458,000 points, and those points are the whole picture.

The aspect ratio is the relationship between width and height, written as two numbers with a colon between them[2]. A 4:5 ratio means five units of height for every four units of width. The 1080 × 1350 px image sits at exactly that ratio, because 1080 divided by four and 1350 divided by five both come to 270.

The two measurements answer different questions and you need both. The ratio decides the shape of the frame, and the pixel dimensions decide how much detail fits inside that shape. A service that accepts 4:5 pictures will therefore take a 1080 × 1350 px file and a 2160 × 2700 px file alike, because the shape is the same in both.

A pixel only gains a physical size on a particular screen or on paper, once a density in DPI comes into play. If the picture is heading for print, work out the size in centimetres with the pixels to centimetres converter.

Once the target dimensions are in place, a bright rectangle appears on the preview. Exactly that part of the picture goes into the downloaded file, and the rest of the image is dimmed. There are four ways to move it.

Dragging the crop. Grab the bright area with the mouse and move it anywhere on the picture. The editor switches itself to the Position tab as you do, so you can see where on the photo the crop currently sits.

The corner handles. Four small squares sit in the corners of the bright area. Dragging any of them changes how much of the original the crop covers, while the shape of the frame stays put, because it follows the dimensions you typed.

The Zoom tab. The Crop zoom field takes values from 100 to 300%. The higher the number, the smaller the slice of the original the crop covers, so this is the field to reach for when you want to pull one particular detail out of a photo.

The Position tab. Two fields describe where the crop sits, as a percentage: Horizontal (X) runs from the left edge to the right, and Vertical (Y) from top to bottom. Three buttons next to them centre the crop horizontally, vertically, or on both axes at once.

However you move the crop, the downloaded file always carries exactly the dimensions shown in the Target row. Zoom and position decide which part of the picture goes into the file, and the size of the result stays as you typed it in the Width and Height fields.

The bright crop area is divided by lines into nine equal parts. This is the rule of thirds, one of the basic ideas in photographic composition: the most important element of the picture, whether a face, a product or the horizon, lands on one of the lines or where two of them meet.

The grid earns its place on frames that a platform trims after you publish them. Knowing that a phone shows a Facebook page cover in a narrower slice, you place the logo on the middle square of the grid and it stays inside the frame on every screen.

The Grid color tab offers five line colours: green, white, black, red and yellow. You change the colour so the lines stay readable on the particular photo in front of you — white works on dark frames, black on bright ones.

The photo stays on your device. Cropping, scaling and saving to a new format are all done by the browser itself, through the built-in canvas element that draws the slice of the image at the target dimensions and turns it into a file[9]. Closing the tab ends the whole operation, because the browser releases the memory holding the image.

Something useful happens along the way. Photos from phones and cameras carry EXIF metadata: the date, the camera model, the exposure settings and sometimes the GPS coordinates of the place where the shot was taken. The browser draws only the points of the image onto the canvas, so the file you download holds the picture and nothing else. We checked this on a photo with EXIF deliberately written into it, and the marker was gone from the downloaded file.

Rotation carries over correctly. Browsers read the orientation flag out of the EXIF data before they display anything[10], and the editor works on what you see in the preview. A photo taken upright on a phone therefore stays upright.

The editor reads JPG, PNG, WebP, AVIF, GIF, BMP and SVG files, which is everything a browser can draw on its own. Photos from an iPhone saved as HEIC open once you put them through the HEIC to PNG converter, and scans stored as TIFF through the TIFF to PNG converter.