How to design a thumbnail viewer in QT

[Lykurg]

By auto-arrange I mean that, if I stretch the window to become wider, the images will automatically form a single row across. If I make the window smaller, the images will form several rows as needed with a vertical scroll bar.

A quick QGridLayout example that I made doesn't do that. Thanks again.

Have a look for the flow layout example. But if you don't have thousends of items, just react on the resize event and calculate the position of the items yourself in a function. ~ 15 lines of code!