Chris Evans was made to look small and skinny as Steve Rogers in "Captain America: The First Avenger" through a combination of innovative filmmaking techniques and visual effects. These included:

• Using a body double named Leander Deeny, who was shorter and skinnier, to mimic Chris Evans' performance for many scenes.
• Filming three passes of each scene: one with Evans, one with the body double, and a clean background shot.
• Digitally scaling down Chris Evans' body to match the smaller frame, including detailed digital adjustments to his skin texture, muscles, and shadows to make him appear much thinner and frailer.
• Using oversized props and set modifications to enhance the illusion of smaller size (e.g., larger helmets and lowered seats).
• Having Chris Evans alter his physical movements on set by walking with bent knees and taking shorter steps to appear smaller.
• Digitally grafting Evans' face onto the body double's frame in post-production, with adjustments to the jawline and neck to avoid disproportional bulkiness.

These combined practical and digital effects allowed Evans to convincingly portray the frail 5'4", 95-pound pre-super soldier Steve Rogers while maintaining the actor's facial expressions and performance.