Flashing the latest Yocto image requires to perform a new method which uses the Flash Tool Lite. Please take a look at the following document where there are more details about the Edison's flashing process: Flashing the Edison Module
The Flash Tool Lite can be downloaded from this site: IoT - Intel® Edison Board Download | Intel® Developer Zone. You will find, under the Flash Tool Lite section, a user's manual too.
Once you have flashed the Yocto image, follow the step-by-step guide to install and use Eclipse. The guide is available in the following site: IoT - Eclipse* User Guide for C/C++ | Intel® Developer Zone