In ASP.NET, ISS sets a maximum upload file by default. We can’t upload files with size more than 4Mb, because it’s already configured in the machine.web file. as follows:
<httpRuntime maxRequestLength =”4096″/> where 4096 in kb
Although you can overload these settings in the web.config file
add in the <system.web>
<httpRuntime maxRequestLength =”5120″/>
Which allows uploading files up to for example 5120 = 5Mb.