is based on feature cloning, 
stealing of ideas and whole dialogs from ACDSee and/or IrfanView! (for example: XnView has been stealing/cloning features and whole dialogs from IrfanView, for 10+ years). 
IrfanView was the first Windows graphic viewer WORLDWIDE with Multiple (animated) GIF support.
One of the first graphic viewers WORLDWIDE with Multipage TIF support.
The first graphic viewer WORLDWIDE with Multiple ICO support.
Some IrfanView features: 
Many supported file formats (click here the list of formats) 
Multi language support 
Thumbnail/preview option 
Paint option - to draw lines, circles, arrows, straighten image etc. 
Toolbar skins option 
Slideshow (save slideshow as EXE/SCR or burn it to CD) 
Show EXIF/IPTC/Comment text in Slideshow/Fullscreen etc. 
Support for Adobe Photoshop Filters 
Fast directory view (moving through directory) 
Batch conversion (with advanced image processing) 
Multipage TIF editing 
File search 
Email option 
Multimedia player 
Print option 
Support for embedded color profiles in JPG/TIF 
Change color depth 
Scan (batch scan) support 
Cut/crop 
Add overlay text/image (watermark) 
IPTC editing 
Effects (Sharpen, Blur, Adobe 8BF, Filter Factory, Filters Unlimited, etc.) 
Screen Capturing 
Extract icons from EXE/DLL/ICLs 
Lossless JPG rotation 
Shell Extension PlugIn 
Unicode support 
Many hotkeys 
Many command line options 
Many PlugIns 
Only one EXE-File, no DLLs, no Shareware messages like "I Agree" or "Evaluation expired" 
No registry changes without user action/permission! 
and much much more