What should I do if the php compressed image is not clear?

In web development, pictures are not only an important element in web page beautification, but also one of the indispensable contents. In order to improve the loading speed of web pages, we usually use image compression technology. However, when some people use PHP to compress images, they find that the compressed images are unclear or even mosaic. This in the end is why?

Cause 1: The file format is incorrect

When compressing pictures, we need to specify the format of the pictures to be compressed. If the format is set incorrectly, it will cause problems with the compressed images. Generally speaking, the image format can be JPEG, PNG, GIF, etc. Among them, for pictures with transparent backgrounds, we give priority to PNG format. For pictures with fewer colors and no translucency effect, you can use the JPEG format. If you choose an unsuitable format, it will cause problems in the compressed pictures, such as mosaics, color distortion, etc.

Reason 2: The compression ratio setting is unreasonable

In PHP, we usually use the imagejpeg() function and imagepng() function to compress images. These functions all accept a compression ratio parameter, which is used to specify the degree of compression of the image. If the compression ratio is set too high, it will cause obvious mosaic phenomenon in the compressed picture; if the compression ratio is set too low, it will cause picture distortion, blurred details and other problems. It is recommended to test and adjust the compression ratio to find the most suitable compression ratio.

Reason 3: Image size exceeds the limit

When compressing images, we need to consider the size limit of the image. If the image is too large, it needs to be segmented and compressed, otherwise it will cause problems with the compressed image. At this time, you can consider reading the image in segments, dividing the image into several parts for compression, and finally splicing the compressed parts together. This can avoid compression problems caused by excessively large images.

Reason 4: Code logic issues

Some people may have logic loopholes when writing PHP code, resulting in unsuccessful image compression. At this time, you need to check the code carefully to ensure that the logic of the program is correct. If you encounter problems, you can refer to the official documentation or ask for help in the developer community.

Summary

When compressing images, try to use the correct format, reasonable compression ratio, correct size limit and correct code logic to avoid unclear problems. If you still encounter the problem of unclear images, you can try using some third-party libraries for image compression. At the same time, pay attention to the usage environment and viewing distance of the picture. Sometimes there is no need to pursue excessive quality.

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