I ran into the same problem yesterday. Here's what I did to flash the latest build successfully on my Nexus 5:
Unzip the image-xxxx.zip file into the same folder where you have your bootloader and radio images. Typically, it will be your platform-tools folder. I, then, issued the commands as:
fastboot flash bootloader bootloader.img
fastboot flash radio radio.img
fastboot flash recovery recovery.img
fastboot flash boot boot.img
fastboot flash system system.img
fastboot flash cache cache.img
fastboot erase userdata
fastboot flash userdata userdata.img
This gave me a brand new full stock image on my nexus 5. With flashing stock with above commands, you will lose all of your data so back it up prior to flashing stock.
Originally Posted by sue4
Does anyone face problem when installing the LMY47I Factory image that says.. "error bla bla bla system.img.. Press any key to exit"? The bootloader and radio were flashed successfully before that. I have tried to install the zip via TWRP 18.104.22.168, either adb sideload mode and copying the zip to the storage 1st, and not successful still. Help needed.. anyone? Please..