UIGraphicsImageContext Memory Spike - Reducing Footprint
your image might have 111 KB compressed as an jpg or a png. But for image processing it needs to be decompressed. It will be loaded into memory with 8 or 16 bit for each color channel. With RGB it would be up to 48 bit per pixel and 8 bit for the alpha cannel in case of png. So 5MB would represent roughly 1.25 million pixel, or something like 1000*1250 pixel.