Changes from preview 4 to preview 5:

What's new

Restored the resize functionality with a redesigned resize window (batch conversion support coming in the next preview release).
Restored the setting to toggle whether showing the hover buttons or not.
Separated Save and Save as options, replacing the Show file saving dialog setting.
Added a new navigation feature to move back or forward by either 50 or 100 images at a time.
Added initial Auto Update functionality in the About window.

Improved performance and fixed bugs in the Side by side comparison mode.
The title for both images are now displayed in Side by side mode.
General UI/UX improvements.
Updated file picking choices, to include all supported file formats when using the Open or Save file dialog (e.g., when pressing Ctrl + S or Ctrl + O).
When navigating to next or previous directory, it will now load files from subdirectories, if no images are found.
Navigation buttons in the bottom bar now support holding down for continuous image switching.
Enabled tab navigation in the Settings window using mouse buttons, allowing back-and-forth movement between tabs.
Determine if using light or dark theme when opening PicView for the first time (or no settings exist)
Start window with minimum size if no settings exists.
Zoom to mouse cursor position when using the Zoom in and Zoom out functions (Numpad + and Numpad - by default).

Fixed window not starting up correctly in full-screen, when the setting is enabled.
Fixed display bugs when switching between animated and static images.
Fixed taskbar progress bar not updating in certain cases.
Fixed button border thickness inconsistencies when using the flip function.
Fixed loading errors when using the file duplication function.
File deletion and file related loading fixes.
Gallery selection, loading and sorting fixes.
Fixed the bottom gallery not closing when entering slideshow.
Fixed Ctrl + Shift modifiers keys working incorrectly.
Improved memory management by fixing unmanaged memory cleanup.
Fixes for display scaling (DPI).

Full Changelog: 3.0.0-RC-preview4...PicView-v3.0.0-rc-preview-5