A weak infrared (IR) image amplifier with more than 60-dB optical gain and frequency up-conversion is developed from a picosecond (PS) 355-nm pumped gated optical parametric amplifier (OPA) in a \beta- BaB2O4 (BBO) crystal. The IR image at 1064 nm is amplified and up-converted into the visible region at 532 nm by parametric amplification and up-conversion. With the optimized optical gain, the lowest detectable energy of the image can be as low as 1.8 femto-Joule per pulse, which is three orders of magnitude lower than the detection limit of a charge-coupled device (CCD) camera. The transversal resolution of the OPA imaging is investigated, and the approaches for higher detection sensitivity and higher transversal resolution are proposed.