Everything opens files via the ShellExecute API
with the NULL verb.
While Windows Explorer will open by invoking the default context menu item.
An option to invoke the default context menu item in Everything (like Windows Explorer) is in development.
For now, you will need to correct the file association in your registry.
What is your default program to open pictures?
In the registry editor (Start menu -> regedit -> right click and run as admin), navigate to HKEY_CLASSES_ROOT\.jpg
What is shown for the Default Value? (eg: jpegfile)
Navigate to HKEY_CLASSES_ROOT\<Default Value from above>
Navigate to HKEY_CLASSES_ROOT\jpegfile\shell
What is shown for the Default Value? (eg: (value not set) or open)
Navigate to HKEY_CLASSES_ROOT\jpegfile\shell\open\command
Double check the command looks correct for the open verb.
Do the same for HKEY_CLASSES_ROOT\.png