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Here we just need a valid image URL. To make sure that your externally hosted images are in compliance with marketplace requirements you will want to have them as HTTPS and not HTTP.
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Step 3 - Upload Your Data
When you click "Client: Import Image Overrides" you will see "Choose File" next to File Upload. Click this button to locate the file on your computer. Double click your file and it will be ready to go.
Enter your email address if you want to be notified when the job is complete. (optional).
Click Submit
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Step 4 - Monitor Job Processing 🏁
You will want to monitor the job that you just ran in File Center as it will be in a Pending or Processing status until the system has completed it. These jobs typically take 30-60 minutes depending on the size of the csv file.
Once finished you will see it Completed or Complete w/ Warnings. Click on the job and you will have access to a Processing Report. Open the report and the success or failure of each line item will be reported.