error when click on check for errors button from marketing email template

Hi,

I am getting below error when click on check for errors button from marketing email template.

I inserted text then click on below marked button as shown in second screen-shot then drag and drop image element from tool box then select the image but when click on check for error button I am getting below error.  Please check this issue and kindly provide step by step process to create image in email and send to CRM contacts.