Thank you for writing in, please inspect your image element and look for the border option and set it to none.
However, I think you’re referring to the page background-image, if so, please navigate to Theme Options > Layout and Design and remove the image that was set on Background Image option.
Please follow one of the methods provided here on How to Increase the Maximum File Upload Size. If none, of the methods, work, please contact your hosting support on how to increase Increase the Maximum File Upload Size effectively.
Yes, you can upload it via FTP or SSH, but make sure you upload the folder pro not the zip file. You can extract it to your local computer before you upload it.
To better assist you with your issue, kindly provide us access to your site so that we can check your settings. Please create a secure note with the following info:
– Link to your site
– WordPress Admin username / password
To know how to create a secure note, please check this out: How The Forum Works
With regards to the background and margins, please take note that your homepage is using Blank - No Container | Header, Footer page template. On the other hand, your inside pages such as the About, Products, Support, etc, are just using the default page template. Please edit each of these pages and change the page template to get rid of the margins and the background image. For more details about the different page templates in the theme, please check this out: