How to make the photos taken no larger than 3m?

In the camera settings attached to the mobile phone, set the photo size to the minimum (for example, 2448×3440) and set the digital resolution to the minimum. You can also edit and cut the photos after shooting, as long as the square frames are around 3 m.

File size is at the expense of image quality. The compression ratio can be as high as 100: 1. JPEG format can easily compress files at the ratio of 10: 1 to 20: 1, and the image quality will not decrease. JPEG compression can handle realistic photographic works well.

For simple works with few colors, strong contrast, solid color borders or large solid color areas, JPEG compression cannot provide ideal results. Sometimes the compression ratio is as low as 5: 1, which loses the integrity of the picture. The reason for this loss is that JPEG compression scheme can compress similar tones well, but JPEG compression scheme can not handle the strong difference of brightness or solid color well.

Extended data

The file can be compressed to the smallest JPEG format. When stored in JPEG format in Photoshop software, the compression level of 1 1 is provided, which is represented by 0- 10. Level 0 has the highest compression ratio and the worst image quality. The compression ratio can reach 5: 1 even if the quality maintenance with almost no loss of details is adopted.

When saving in BMP format, you will get a 4.28MB image file. When saved in JPG format, the file size is only 178KB, and the compression ratio reaches 24: 1. After many comparisons, eight-level compression is the best ratio of storage space and image quality. The advantages of PG file are small size and good compatibility.