The CSV should ideally have a header row having the column names.
Each column's data in data rows should be clearly separated from other columns by comma.
If you have to use comma for value or set of values that you need to be used for a column, then you should enclose the entire set of values (separated by comma) in double quotes, to make it look like a group of values that represent one column. The cases where you may need to use comma to separate values in a single column are when you provide value(s) for fields that are of a type that allows multiple options to be stored like "check box" or "multiple choice option box"; or any other text field for that matter.A sample CSV file is attached with article.
Being on website's administrative panel, you can use Import CSV option under "Others" menu.
On this page, you can upload the file and select category, user (poster) and status for the listings. If your CSV holds the column headers then you should check "Has Headers".
Once done you can hit "Import", you will then be redirected to a page where you can map the columns of CSV to the fields to be used for listings.
A properly mapped fields form would look like this :
Once mapped you can then click "Save", this will trigger the import process.
When the process finishes it will bring the results to you (both in case of success or failure). For all successfully operations you should see a corresponding listing created.
Before moving ahead with process of importing listings for which the images should be fetched and uploaded automatically, please make sure that the folder /app/webroot/uploads has permission set to 0777 recursively.
The next thing required is to simply keep a column in CSV for the URL where the image for the listing is to be fetched from (the URL should however be accessible).
When you would map the fields at the time of CSV import, you will be prompted to select a column that is to be used for "URL of image", once mapped the image will be fetched for listing automatically from the given URL.
Attached sample CSV file can be used as reference.