Add new Product if no existing product is there in existing Magento store.
Go to System > Data Transfer > Export
Select entity type as product and click on on continue button that is in the bottom of the page. Once you click on continue button you can download the csv file of exported products . Use the exported sheet for reference to fill the values and then fill yours values accordingly , fill image name with file extension as .jpg or .png etc as mentioned in this screenshot:
then go to var folder create one folder having name ( import ) and place the image having same name as mentioned in the import csv file and then
Go to System > Data Transfer > Import
and select entity type as an product select import behavior as per yours need and then browse for file from Select File to Import browse option after this enter the path of import folder in our case it is var/import in the Images File Directory text box as mentioned in the following screenshot :
Then click on check data button on top right corner. If you did everything correct you will get this screen
Click import button and then do reindexing using CMD:
php bin/magento indexer:reindex
and then flush the cache:
php bin/magento cache:flush
and then check yours frontend it will show imported products with images.