1. If your picture is large, you can select the cropping function, and the cropping length is set to 500*200/500*300. If it is not big enough, you can cut it according to the ratio of 5:2/5:3. For example, if you set 1000*400, you can click the zoom button once on the basis of 500*200/500*300, and so on. Click it as many times as you want. This is exclusive to image designers (such as Meitu Xiu Xiu).

2. If your editor has the function of "changing the image size", just set the image size according to 500*200/500*300.