Resizing means change the size of the video, making it either larger or smaller in dimension When you change the size, the file size will increase or decrease according to the final size of the video.
Video compression refers to reducing file size. A video file in RAW format needs more space because it has complete information. When the compression is complete, some frames are deleted without affecting the information in the video.
During the compression process, the file size becomes shorter, but the video size remains the same.