This issue could be caused by Windows 10 choosing accent color, to disable this feature: Open Windows 10 Settings, then Personalize, in the Colors section turn off "Automatically pick an accent color from my background". Also transparency effects could cause some lag.
Outdated display adapter drivers could also cause this issue, check if there is an updated version of the drivers.
Unfortunately there is no way for applications to have the same numbering used by windows, the official Microsoft answer is "It was never a design goal to provide a way for applications to label monitors with the same IDs that the screen resolution control panel uses". Starting from v4.2.3 WallpaperSS displays position and size of the selected monitor this should help to identify it.
You have a wide monitor with 2.38:1 aspect ratio while most pictures have 3:2 or 4:3 aspect ratio, by default WallpaperSS displays colored bars on both sides but it has an autoresize function that allows you to choose how resize pictures that doesn't fit to screen. Open the WallpaperSS settings window, click on Options the Auto Resize. In this page select the option "Stretch and Crop the image to fit the screen", choose the amount of strech/crop then click on the icon on the right of the limit value. This window allows you to easily calculate the limit used by WallpaperSS to decide whether an image may be cropped/stretched or not.
The window displays the aspect ratio of your monitor, 2.38:1 in your case, usually you don't need to move the top slider since it is already set to the aspect ratio detected by WallpaperSS. To adjust the limit value move the second slider to the aspect ratio of the pictures you wish to be cropped/stretched. All pictures with aspect ratios on the left will be cropped/stretched as well.
Starting from Wallpaper Slideshow Pro version 5.1.0 it is possible to set wallpaper position to "Auto Fit", in this way all images are resized to fit to screen without black bars.
It is very easy to remove the colored bars by configuring WallpaperSS to stretch ( or crop ) your pictures. Open the WallpaperSS Pro configuration window then open the Options window Auto Resize section . Here you can choose either "Stretch and crop image to fit the screen".
Depending on the aspect ratio of your images and your monitor it is possible you need to change the value in the field "Limit for image stretching/cropping:". If the default value doesn't work (ie. images are not stretched/cropped) try raising it, here are some typical values for the Limit field:
18 : Allows to stretch/crop images with 16:10 aspect ratio
28 : Allows to stretch/crop images with 16:10 or 3:2 aspect ratio
45 : Allows to stretch/crop images with 16:10, 3:2 or 4:3 aspect ratio
Starting from Wallpaper Slideshow Pro version 5.1.0 it is possible to set wallpaper position to "Auto Fit", in this way all images are resized to fit to screen without black bars.
"Auto resize": WallpaperSS checks images aspect ratio and compares to your monitor aspect ratio, if they differ too much image is resized retaining its original aspect ratio and black bars are added.
"Auto Fit": WallpaperSs always resizes images according to Stretch/Crop settings to fit the screen. Black bars are never added.
Yes, it is possible by using filters. In the Filters section of the Options window select monitor #1, enable the options Include and Full File Name Contains then in the text box enter an expression to identify your folder, for example if folder name is folder1 enter: *\\folder1\\*
Do the same for monitor #2 but enter the name of the second folder: *\\folder2\\*
Yes, Wallpaper Slideshow offers a nice solution. Wallpapers can be assigned to groups, then with a hokey it is possible to switch group and set a new wallpaper choosen from the new group.
Wallpaper Slideshow Pro can handle a large number of files and the only limit is 2Gb memory limit of 32bit programs. Another limit is the time needed by the program to scan the hard disk and build the files list. To give you some numbers on a fast computer Wallpaper Slideshow can easily handle 100,000 files and can be used with some delays with 1,000,000 files.
