PHP to store images in MySQL or not?

Question

I have built a small web application in PHP where users must first log in. Once they have logged in, I intend on showing a small thumbnail as part of their "profile".

I will have to ensure the image is below a particular size to conserve space, or ensure it is a particular resolution, or both, or even perhaps use something like image magick to scale it down.
Not sure what the best approach for that is yet, any ideas welcome.

Also, I have been trying to work out if it is better to store the image in the users table of MySQL as a blob, or maybe a separate images table with a unique id, and just store the appropriate image id in the users table, or simply save the uploaded file on the server (via an upload page as well) and save the file as theUsersUniqueUsername.jpg. Best option?

I found a tutorial on saving images to mysql here: http://www.phpriot.com/articles/images-in-mysql

I am only a hobby programmer, and haven't ever done anything like this before, so examples, and/or a lot of detail is greatly appreciated.

Solution 1

Always depends of context, but usually, I store a user image on the filesystem in a folder called /content/user/{user_id}.jpg and try to bother the database as little as possible.

Solution 2

I would recommend storing the image as a file and then have the file URI in the database. If you store all the images in the database, you might have some problems with scaling at a later date.

Check out this answer too:

Microsoft's advice for SQL Server used to be, for speed and size, store images in the file system, with links in the database. I think they've softened their preference a bit, but I still consider it a better idea certainly for size, since it will take up no space in the database.

Solution 3

The overhead using BLOB is a lot less than most people would have you believe, especially if you set it up right. If you use a separate server just running the DB to store binary files then you can in fact use no file-system at all and avoid any overhead from the file-system

That said the easiest/best way unless you have a couple of servers to yourself is storing them in the filesystem

• Do not store the absolute URL of the file in your DB, just the unique part (and possibly a folder or two), e.g. 2009/uniqueImageName.jpg or just uniqueImageName.jpg. Then in your pages just add the host and other folders onto the front, that way you have some flexibility in moving your images - all you'll need to change is a line or two in your PHP/ASP.NET page.

• There is no need to store outside the document root for security - a .htaccess file with DENY FROM ALL will work the same and provide more flexibility

• No need to 'shunt' images so much for security, just have a getImage.php page or something, and then instead of inserting the actual URL in the src of the image, use something like getImage.php?file=uniqueImageName.jpg. Then the getImage.php file can check if the user is authorised and grab the image (or not).

• Use a name which is guaranteed to be unique (preferably an integer i.e. primary key) when storing, some file-system (i.e. Windows) are case-insensitive, so JoeBloggs.jpg and joebloggs.jpg are unique for the database, but not for the file-system so one will overwrite another.

• Use a separate table for the images, and store the primary key of the image in the users table. If you ever want to add more fields or make changes in future it will be easier - it's also good practice.

If you are worried about SEO and things like that, store the image's original file name in another field when you are uploading, you can then use this in your output (such as in the alt tag).

Solution 4

Challenging the Conventional Wisdom!

Of course it is context dependent, but I have a very large application with thousands of images and documents stored as BLOBS in a MySQL database (average size=2MB) and the application runs fine on a server with 256MB of memory. The secret is correct database structure. Always keep two separate tables, one of which stores the basic information about the file, and the other table should just contain the blob plus a primary key for accessing it. All basic queries will be run against the details table, and the other table is only access when the file is actually needed, and it is accessed using an indexed key so performance is extremely good.

The advantages of storing files in the database are multiple:

1. Much easier backup systems are required, as you do not need to back up the file system
2. Controlling file security is much easier as you can validate before releasing the binary (yes, you can store the file in a non-public directory and have a script read and regurgitate the file, but performance will not be noticeably faster.
3. (Similar to #1) It cleanly separates "user content" and "system content", making migrations and cloning easier.
4. Easier to manage files, track/store version changes, etc, as you need fewer script modifications to add version controls in.

If performance is a big issue and security and backups aren't (or if you have a good fs backup system) then you can store it the the FS, but even then I often store files (in the case of images) in the DB and building a caching script that writes the image to a cache folder after the first time it's used (yes, this uses more HD space, but that is almost never a limiting factor).

Anyway, obviously FS works well in many instances, but I personally find DB management much easier and more flexible, and if written well the performance penalties are extremely small.

Solution 5

We created a shop that stored images in the DB. It worked great during development but once we tested it on the production servers the page load time was far too high, and it added unneccessary load to the DB servers.

While it seems attractive to store binary files in the DB, fetching and manipulating them adds extra complexity that can be avoided by just keeping files on the file system and storing paths / metadata in the DB.

This is one of those eternal debates, with excellent arguments on both sides, but for my money I would keep images away from the DB.

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