Hello umbraco-fellas!

It seems there might be some problems with v7.3 which we didn't encounter before with any other version. We're using same hosting provider for older umbraco instances.

Long story short, for every single image a website displays we get Access Denied, which appears to be generated by lack of permissions for ImageProcessor, this is an stack trace of an error we get:

[Win32Exception (0x80004005): Access is denied]
   System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo) +1789
   System.Diagnostics.Process.Start() +6826110
   ImageProcessor.Web.PostProcessor.PostProcessor.RunProcess(String sourceFile, Int64 length) +325
   ImageProcessor.Web.PostProcessor.<PostProcessImageAsync>d__0.MoveNext() +447
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52
   System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task) +10520988
   ImageProcessor.Web.HttpModules.<ProcessImageAsync>d__11.MoveNext() +3752
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52
   System.Web.TaskAsyncHelper.EndTask(IAsyncResult ar) +60
   System.Web.AsyncEventExecutionStep.OnAsyncEventCompletion(IAsyncResult ar) +9693201

We added in web config this lines which appeared to fix a problem, but not for long:

<!-- ImageProcessor.Web intercept module references -->
<configuration>
  <system.web>
    <httpModules>
      <add name="ImageProcessorModule" type="ImageProcessor.Web.HttpModules.ImageProcessingModule, ImageProcessor.Web"/>
    </httpModules>
  </system.web>
  <system.webServer>
    <validation validateIntegratedModeConfiguration="false" />
    <modules>
      <add name="ImageProcessorModule" type="ImageProcessor.Web.HttpModules.ImageProcessingModule, ImageProcessor.Web"/>
    </modules>
  </system.webServer>
</configuration>

Any idea?