There are times when you just want to update the thumbnail images that magento uses on the category pages as well as on product pages.
The default magento dataflow won’t let you do that, but you can use magento’s fast import process, which will allow you to update specific information on a product.
Your spreadsheet should have the following columns:
Please note that _store, _attribute_set and _type should be blank, so you don’t overwrite existing values.
If you want to exclude the thumbnail from appearing in the more views block make sure to put a 1 in media_is_disabled column (this will prevent them from loading into the more views block as a thumbnail).
Then fill in the remaining columns with the new image info. See example download.
Image Update Spreadsheet (190)
This example file contains completed columns for one product, which you can use an example to start with
(To use file as a csv, changed the name of file to fast-import-images-exclude.csv and open it using open office or excel).
Once you have a finished your own csv, login to your store’s admin. In upper menu dropdown, go to System > ImportExport > Import.
Next step is to browse and select a spreadsheet to import. Once you have selected the spreadsheet to import, click on Check Data button.
Magento will import your spreadsheet and validate it to make sure there are no errors. If there are errors, you will need to fix them.
If there are no errors, you can click on Import to update products listed in spreadsheet.
Magento’s fast import can process a large number of rows very quickly, so it won’t take long to update images.