Application forms want a photo of an exact pixel size, social profiles crop anything that is the wrong shape, and website banners need to fit a fixed slot. Resizing is the simplest way to meet those requirements without buying software. This tool changes the dimensions of your image to exactly what you need, either by typing pixel values or scaling by percentage.
Keeping the aspect ratio locked prevents stretching. Only unlock it if you deliberately want a different shape.
Yes, though enlarging beyond the original size will always look softer, because the extra detail does not exist in the file.
Usually yes, since fewer pixels means less data. Combine it with compression for the smallest result.
The common image formats such as JPG, PNG and WebP.