Where can I find $NopResources

If am trying to find the location of $NopResources to make changes to the text. For example:

$NopResources:Admin.ProductPictures.UploadButton.Text
$NopResources:Admin.ProductPictures.New.DisplayOrder.RangeErrorMessage
$NopResources:Admin.ProductPictures.UploadButton.Tooltip

Thanks.

Go to admin area > Content Management > Localization. All resource strings are there

Thank you.