Hi Kamei,
No one has ever implemented ResNet on Loihi that I know of, either with the converter or otherwise. As you said, if you use “valid” padding your output will shrink after each layer, and ResNet has so many layers that by the end, the shrinkage will be too much. I’ve implemented “same” padding for nengo.Convolution in NengoLoihi in the same-padding branch.