PHP Image Optimizer

We are building a web app which will have a lot of images being uploaded. Which is t开发者_如何学Pythonhe best Solution to optimize these images and store it in on the website ?

And also is there a way i can also auto enhance the images which are being uploaded ?

1. Do not store images in DB, store them in file system (as real files). You'll probably need to store information about them in DB though, e.g., filename, time of upload, size, owner etc.
2. Filenames must be unique. You might use yyyymmddhhiissnnnn, where yyyymmdd is year, month and date, hhiiss - hour, minutes and seconds, nnnn - number of image in that second, i.e., 0001 for first image, 0002 for second image etc. This will give you unique filenames with fine ordering.
3. Think about making some logic directory structure. Storing millions of images in single folder is not a good idea, so you will need to have something like images/<x>/<y>/<z>/<filename>. This could also be spanned across multiple servers.
4. Keep original images. You never know what you will want to do with images after year or two. You can convert them to some common format though, i.e., if you allow to upload JPG, PNG and other formats, you might store all of them as JPG.
5. Create and store all kinds of resized images that are necessary in your website. For example, social networks often have 3 kinds of resized images - one for displaying with user comments in various places (very small), one for displaying in profile page (quite small, but not like icon; might be some 240x320 pixels) and one for "full size" viewing (often smaller than original). Filenames of these related images should be similar to filenames of original images, e.g., suffixes _icon, _profile and _full might be added to filenames of original images. Depending on your resources and the amount of images that are being uploaded at the same time, you can do this either in realtime (in the same HTTP request) or use some background processing (cron job that continuously checks if there are new images to be converted).

As for auto enhancing images - it is possible, but only if you know exactly what must be done with images. I think that analyzing every image and deciding what should be done with it might be too complex and take too much resources.

All good suggestions from binaryLV above. Adding to his suggestion #5, you also probably want to optimize the thumbnails you create. When images are uploaded, they are likely to have metadata that is unnecessary for the thumbnails to have. You can losslessly remove the metadata to make the thumbnail sizes smaller, as suggested here: http://code.google.com/speed/page-speed/docs/payload.html#CompressImages. I personally use jpegtran on the images for my website to automatically optimize my thumbnails whenever they are created. If you ever need the metadata, you can get it from the original image.

Something else to consider if you plan to display these images for users is to host your images on a cookie-free domain or sub-domain as mentioned here: http://developer.yahoo.com/performance/rules.html#cookie_free. If the images are hosted on a domain or sub-domain that has cookies, then every image will send along an unnecessary cookie. It can save a few KB per image requested, which can add up to a decent amount, especially on restricted bandwidth connection such as on a mobile device.