What a flip actually does to the pixels
Flipping horizontally reverses each row, so the pixel at column x lands at column width - 1 - x. Flipping vertically does the same to columns, swapping the top and bottom rows. The canvas keeps the original width and height, nothing is rotated, and the tool does it by drawing the picture with a scale of -1 on one or both axes around the canvas centre. Switching on both flips is the same as turning the image 180 degrees.
Worked example
A 1000 by 500 image has a logo whose left edge sits at x = 100. After Flip horizontal the logo's right edge is at x = 900 and its text reads backwards. After Flip vertical instead, the logo keeps x = 100 but moves to the opposite side of the image vertically, and the picture is upside down along that axis only. The file stays 1000 by 500 in both cases.
| Setting | Result | Typical reason |
|---|---|---|
| Horizontal only | Left and right swap | Make a subject face the other way in a layout |
| Vertical only | Top and bottom swap | Water reflections, upside-down effects |
| Both | Same as a 180 degree turn | Fix an image captured upside down |
| Neither | Unchanged copy, re-encoded | Quick format change only |
Selfies, text and other cases where a flip matters
Front cameras show a mirrored preview, but many phones save the photo the right way round, so the saved file may look "flipped" compared with what you saw when posing. Whether yours does is a camera setting, so look at the result before deciding. Text inside a flipped photo will read backwards, which is fine for a mirror effect but a problem for signs and screenshots. Flipping a face photo can also change how the person appears, because faces are rarely symmetrical.
Limits and details
- Both flips start off when you load a file, so nothing changes until you press a button. That also means loading a file just to change its format gives you an unflipped copy.
- Each button turns bright when its flip is active; press it again to switch it off.
- Output defaults to the format of your upload, JPG, WebP or PNG. JPG exports get a white background and are saved at a fixed 92 percent quality, so repeated flipping of a JPG adds a little compression each time. Keep the original and flip once.
- Transparent PNG and WebP images keep their transparency after flipping. The download keeps your file name with
-flippedadded; if the browser cannot encode WebP it saves a PNG and says so. - Photos whose EXIF tag says "rotate 90" are shown upright by current browsers before the flip is applied, so the flip happens on what you see. Details are in the rotate tool notes.