我应该在每次请求时动态生成每个缩略图，还是将它们存储在图像上传中？ [重复]

Question

This question already has an answer here:

• PHP image resize on the fly vs storing resized images 4 answers

Problem - I wanted to set up an image-uploading feature in my website. But I wanted to show both- the original image and a small thumbnail of the image.

Choices - Which way is better - to create a separate image (thumbnail) in a directory when the image is uploaded or to show a smaller version by reducing its height and width in the fixed ratio every time the image is requested?

How I am doing it currently - The later one sounds better to me because it won't be taking much size on the disk but it has to resize the image again and again. Which one do you think is better?

This is a general question for web application, no language in specific.

Any idea how facebook or google do it?

Question - My question is how to generate thumbnails and show them on a website - by creating a copy of the original image with smaller dimension or by generating the thumbnail dynamically every time it is requested.

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Answer 1

Creating the thumbnail on upload is almost always the better option. If storage is a concern you could convert them on the request and then cache the result in a memory store. If its requested again before the cache expires, no conversion will be needed.

Storage is often pretty cheap, so I would probably not go for that extra complexity.