Asp.net MVC page is giving Mime type warnings for image files

Question

While I do not see any functionally or jquery UI elements affected by this, but when I access my asp.net mvc web page the chrome developer console is logged with a bunch of error messages like so:

Resource interpreted as image but transferred with MIME type application/octet-stream.

All of the warnings are for jquery UI images (though I don't have any custom images on there so I don't know if it's jquery UI only). All the jquery images still load correctly.

Does anyone have any insight on why this is happening?

Autoionization

Have you used firebug to look at the response headers for your images? – Naga

I've only used the chrome dev console. Either way what would I be looking for? – Autoionization

Answer 1

Are you running your site from Visual Studio's built-in web server? Apparently, you don't have much control over the MIME types in that environment (see this). I was seeing the same behavior and was starting to stress about it before finally realizing that I wasn't even looking at the IIS-hosted application.

Jasso

Yep this is all when using the VS's built-in web server! Thanks! – Autoionization

I had the same issue with .png files. IIS defaults to sending the correct MIME type for them, so just ignore the warning on the ASP.NET Development Server. Note that this highlights it's worth testing your app in IIS as well! – Pertinacious

Is there any advantage to using the development server instead of just running a local IIS and using that in Visual Studio? – Autoionization

Simplicity, if you are referring to the Cassini web server. No setup, no virtual directories, just F5. – Jasso

to solve the lame-ness of Cassini (Dev Server) & the elevated privileges required for IIS, Microsoft created IIS Express, which is very close to a real IIS, but simpler to setup & you don't need to run VS as administrator to use it. – Mitra