上传图片大小问题

Question

I built a website which allow people to upload their photos using php, but the phots can't be successfully uploaded if the image size is too big, how can I avoid that problem, how can I make the people upload the image without the size limitation, could you show me some php code relevant to that if possible, thanks!

Answer 1

This is possible with .htaccess. You'll need to add the following lines to your file:

<IfModule mod_php5.c>
    php_value upload_max_filesize 20M
</IfModule> 

Although it's probably better to increase the script execution time (so it doesn't time out waiting for the upload) and the maximum POST size, thus:

<IfModule mod_php5.c>
    php_value upload_max_filesize 20M
    php_value post_max_size 20M
    php_value max_execution_time 120
</IfModule> 

This sets the maximum execution time to two minutes, which is a very long amount of time, however this is just an example.

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PHP solution (won't work - see comments)

First, turn on error checking; this will let you know what's happened and where by putting this at the top of your script:

error_reporting(E_ALL);
ini_set('display_errors', '1');

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You'll need to change the upload_max_filesize and the post_max_size declarations in your php.ini (assuming you're using Apache).

Find a lines that look similar to this:

upload_max_filesize = 2M
post_max_size = 8M

And change it to something like:

upload_max_filesize = 20M
post_max_size = 20M

This sets the upload limit to 20MB (which is rather large, I must say). If you're on shared hosting, it's very unlikely they'll allow you to edit php.ini. In this case, you can use ini_set() like such:

string ini_set('upload_max_filesize', '20M');
string ini_set('post_max_size', '20M');

This will set the upload limit to 20MB, or whatever you want to set it to.

(Thank you to @Phil in the comments) Do note that upload_max_filesize must be less than or equal to post_max_size.