The problem doesn’t actually lie in the WordPress coding, it seems to lie within the settings of the webserver that is dishing out your files. Fortunately there is simple answer to this and it lies in doing a quick edit in your .htaccess file.

It seems that some hosting accounts have SecFilterScanPOST enabled and this is causing the problem.

Alter your .htaccess file by adding these two lines of code:

SecFilterEngine Off

SecFilterScanPOST Off

Now try to upload your picture again and you should find it working.

Please note: I’m not a webserver techie and I have to hold my hand up and honestly say that I’m not sure why turning off these two options makes the difference. I do know that they were on for a reason – that reason may be because it’s a default install and they can be either on or off without making any difference, or it could be that it’s a critical bit of set up that really shouldn’t be turned off.

So here is a shout out to anybody with webserver knowledge to join in the comments on this post and tell me what’s what with these settings. So please follow this post’s comments in either the comments RSS feed or subscribe to the comments below.

As with any of our advice the usual disclaimer applies: back up before you do any alterations and be aware that you do the mod at your own risk.