MIME type warning in chrome for png images
I encountered this while running an ASP.NET WebForms app using the ASP.NET Development Server.
I suspect something similar will happen if you use IIS Express as your server as well (VS 2010 SP1).
I 'resolved' my problem locally by editing the project settings (under Web) and changed from the ASP.NET Development Server to IIS on my local machine. I can see that PNG was already defined correctly as an image MIME type and indeed when I hit my local IIS server it's serving up the file with the correct type.
This warning is telling you that your web server isn't configured to send the correct MIME type meta data for PNG images. You should probably consult the administrator for your web server and ask them to set the correct MIME mapping
I added types like this in .htaccess (AddType image/type extention)i.e.
AddType image/png curAddType image/svg+xml svg svgz