Unhelpful error message for images with "hidden" attribute

Prerequisites

• I have written a descriptive issue title
• I have searched open and closed issues to ensure it has not already been reported

System information:

• Windows OS version: Win10 Ver 1803 64x Education
• ImageGlass version: 6.0.2.19

To Reproduce

Steps to reproduce the behavior:

1. install ImageGlass
2. set ImageGlass as standard program for PNG images
3. enable the display of "hidden" NTFS files in Windows Explorer
4. double-click on a hidden PNG image in Windows Explorer so that ImageGlass opens to display it.

Actual behavior:

1. Case 1 for SMB network drive: black image/background of dark theme
2. Case 2 with local hard drive: "ImageGlass cannot open this image because the file is damaged, incorrect or not supported" better said the german original description "ImageGlass kann dieses Bild nicht öffnen da die Datei beschädigt ist, fehlerhaft oder nicht unterstützt wird."

Expected behavior:

1. Option A: The image is displayed like any other. (maybe the function "Show hidden images" is automatically activated temporarily.)
2. Option B: An error message also appears via a SMB network drive. The error message should point to the "Show hidden images" feature in both cases.

Screenshots:

default:

"hidden"-Attribute on local hard drive

"hidden"-Attribute on network drive

Additional context:

See #187 and #441
Behavior was not validated with NFS network drives supported by Windows 10 Pro.

Start by reviewing the related issues #187 and #441, then reproduce the hidden-PNG behavior on a local drive and an SMB network drive using the listed steps. Done means hidden images behave consistently or both cases provide an error that points to the “Show hidden images” feature.