Image height is the number of pixel rows in a picture, counted from the top edge to the bottom edge. Together with the image width, it gives the size of the picture in pixels.
Image Height is not the same as the file size. The file size counts the bytes in the file, while the height counts pixels.
Which files carry it
Almost every image format stores the height in a header, next to the width. Each format keeps it in its own place.
- JPEG: the start of frame (SOF) segment stores the number of lines in the picture.
- PNG: the IHDR chunk, which must be the first chunk in the file, stores the height as a 4-byte whole number.
- GIF: the logical screen descriptor stores the height of the area that all frames of the image are drawn on.
- WebP: the VP8, VP8L, or VP8X chunk stores the height, depending on the kind of WebP file.
- BMP: the bitmap header stores the height right after the width.
- TIFF: tag
0x0101in the first image directory (IFD0) stores the height. The Exif standard calls this tagImageLength. - MP4 and MOV: the header of each video track stores an image height. AVI keeps one in its main header.
What the value looks like
The value is a whole number of pixels, shown without a unit. For example, 682 means that the picture is 682 pixels tall.
Each format sets its own upper limit. A JPEG can declare up to 65535 lines. A lossless WebP image can be up to 16384 pixels tall, and a PNG up to about 2.1 billion pixels.
Many photos also show a row called Exif Image Height. The camera or software writes this tag, 0xa003, into compressed files such as JPEG. It records the valid height of the image, which in a JPEG should match the number of lines in the frame header.
A portrait photo can store a height that is smaller than its width. The orientation tag then holds a value such as 6, which tells a viewer to rotate the picture 90 degrees clockwise. After the rotation, the height you see on screen equals the stored width.
Where the value comes from
The device or program that creates the image writes the height. A camera or phone writes it when it saves a photo. An image editor writes a new value when you crop, resize, or export a picture.
The height describes the pixels themselves. Some programs can edit the Exif Image Height number without changing a single pixel, but the picture stays the same size. To change the Image Height, you resize or crop the picture, and the software then writes the new value.
Why it matters for your file
The height and the width together set how much detail a picture can hold. The Image Size row combines both values, and the Megapixels row is calculated from Image Size.
For printing, the height works together with the Y Resolution. That value is the number of pixels per inch or per centimetre in the height direction. Divide the image height by the Y Resolution to get the printed height in the same unit.
Websites, upload forms, and printing services often ask for a minimum or maximum height in pixels. The Image Height row lets you check a picture against such a limit before you send it.
Video files also carry Height and Coded Height values for each video stream. The Height article covers the general Height value.