A rose can be photographed so closely that its growing habit disappears. Before buying from a flower photograph, ask to see a mature plant and confirm the named cultivar.
A climber, a spreading shrub and a compact rose may offer similar colours but need different space and support. Work out where the plant will grow before choosing the flower you like best.
Ask about the second display
Does the rose normally repeat flower, or is its main show concentrated in one period? Ask about local performance and what the seller means by a long flowering season. Occasional later blooms are different from a consistently full display.
Check whether the photograph shows several stems arranged together or one flower still attached to the plant. Both can be attractive, but they answer different buying questions.
Write the cultivar name next to its expected height and width. If you cannot find that information, pause the purchase rather than assuming the small nursery plant will remain small. Keep the label after planting so photographs of the first season can become a usable record.
Related reading: Rose Varieties in Pictures: Flower Colour and Growth Habit.