Two-dimensional imagers for aircraft corrosion inspection with thermal neutrons have been developed. The neutron detection system consists of a gaseous detector coupled to a solid neutron converter. The neutrons hitting a gadolinium foil are converted into 70 keV electrons which induce an electronic avalanche process in the gaseous counter. The avalanches are detected and localized giving a two dimensional digital image. The imager was tested in two different versions, one with a surface of 32 cm × 16 cm, a dynamic range of 16000, and a spatial resolution of 2.54 mm in each direction. The other has a size of 20 cm × 20 cm, a dynamic of 256 and an enhanced spatial resolution of 1 mm. With this principle, imagers up to a size of 100 cm × 100 cm are feasible. The acquisition time for an image in both cases is typically a few tens of seconds using a neutron flux of 10’ neutrons/cm2/s. The final system including the neutron generator is compact enough to be transportable