Larger thumbnails get more clicks

A small thumbnail asks the user to take a leap of faith. "Click to see what this actually looks like." A larger thumbnail shows enough detail that the click becomes confirmation, not discovery.

This is especially true on category pages where products compete for attention. The product with the largest, clearest image gets the click because the eye goes to what it can process fastest. A 200px thumbnail loses to a 280px thumbnail not because of the size itself, but because of the detail visible at that size.

The trade-off is fewer products visible per screen. But a screen showing 12 products where 3 get clicked beats a screen showing 20 products where 1 gets clicked. Visibility per item matters more than items per screen.

On mobile this effect is amplified. Small thumbnails on a phone screen are nearly impossible to evaluate. Two columns of large images outperform three columns of small ones because the user can actually see what they're looking at.