Image soruce is from webresource.axd?

Question

Hi All,

I'm working with a Datetime picker control(GMDatepicker) developed by Graymattersoft.

Since 2 years we are using this control and didn't face any problem. suddenly don't know what went wrong this datetime picker control's Previous and Next button's image are not showing all other things working fine. 

It showing the Previous and Next button's image fine in development environment for all the browser(IE, firefox, chrome, safari)

But in production environment the Previous and Next button's image image not showing only in IE and Safari.

When i opened the datetime picker control in firebug and found the following code:

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<div style="cursor: pointer;" onclick="javascript:CallServer_ctl00_ContentPlaceHolder1_ProgramsRightControl_dtpExpDate('6/1/2015')"><img src="/WebResource.axd?d=NqRMyHLNHoSISwE0i2VGnvwmBLwjVu_VjBICf2AKNV40fIOrSG7VENXG3rjulI3b8EOpTI1SkswPgxm1l9kC2btVkO0C15BiTcW7rjvWTakjb7RzBoA_gmoC-81lAMX79Izz6Q2&amp;t=633609064760000000"></div>   

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Please help us in fixing this issue.    Thanks in advance...