A live photo on iPhone can have lower quality, and you may even notice that it is pixelated. The reason is that when you take a live photo, the camera records a video and takes a picture, then composes them together. Photos and videos can have different resolutions, for example, the still frame can have a resolution of 4032 × 3024 pixels, while the video clip has a resolution of only 1920 ×  11440  pixels. As a result, it might seem that the photo is of lower quality.