There is already a folder for images in the root directory... no need to create a new one.
C-Panel and FTP are DIFFERENT programs and DIFFERENT protocols.
You need to go get a FTP program (Filezilla is free, but as I said, it has poor security - that's why we use Ipswitch's WSFTP-Pro) and you need to install that program on your home computer (or your office computer - wherever you are working from).
You then use that FTP program to load the images to your images folder (the one that is already there - see above...).
The image FILE NAME (not the actual image FILE itself) must be represented in the database. Remember... this is just the NAME of the image, which is not the same thing as the image itself... and Easy Populate is a quick way of inserting these IMAGE NAMES into the database.
The ACTUAL image file - the binary code that generates the picture - lives in the "images" folder.
What happens is that when a page is assembled by the code for any given page display, the process of assembly (of the resultant HTML) needs to insert the IMAGE NAME of the relevant product image, into the html, and it "collects" this name (which is just a string of text) from the relevant database table, and it strips that "text into the relevant <img src... > tag.
When the compiled HTML is delivered to the browser, the <img src="xxxxxxx.jpg> element calls the actual binary file of the image to render on-screen.
I don't know what this "core ftp" is, but it sounds like something to avoid. Either use Filezilla or WSFTP-Pro.
As mentioned in my previous post, Easy Populate (or Apsona ShopAdmin) are tools for MASS UPLOADING of info into the database, so when you have a LOT of info (which could include the FILENAMES of images) that needs to be populated into the database, it is quicker to use these tools than it is to upload product info one-at-a-time in the conventional way - which is through your shop's ADMIN PANEL and the PRODUCT ADD/EDIT screen.
Of course, you can use this standard interface to load one... two... or twenty thousand poducts into your store - but the more there are to do, the longer it will take. Mass-upload systems do the job far more quickly. Whether you use such mass-upload systems is entirely up to you.
Image handler operates in the background, and all it needs is to have a single, good-quality and relatively large, image, loaded into the main images folder.
I can't make it any more simple... The procedure and protocol is standard webmastership.