For Portfolio and Blog Grid Columns, the amount of columns can be freely selected and range from 1-6 columns. However, the amount of columns that will display depends entirely on the available width of the page. This is general responsive behavior and is completely normal. For example, if you select Portfolio 5 Column and have a site width of 1100px, then you will see 5 columns of images when viewing it on normal size desktop screens, but will see less when viewing it on smaller screen sizes.
The theme will continuously recalculate the size of the columns when you resize the window until it reaches a breakpoint. When it reaches a breakpoint, it will automatically move 1 column to the next row. So 5 columns breaks down to 4 columns, then 3 columns, then 2 columns and all the way down to 1 column on mobile sizes.
As explained above, the theme will continuously recalculate the size of the columns when you resize the window until it reaches a breakpoint. You can manually set a responsive breakpoint for the grid to control when it will start to break into smaller amount of columns. Please take note, however, that further breakpoints are calculated automatically. To learn more about this option, please view our Responsive Breakpoints article.