Illegal string offset problem in Arcade Basic Theme

Hello,

Recently, I have noticed that wordpress finds an http problem when we try to upload a new image. Investigating about the possible cause of the problem, we found the following message, which shows that it could be related to Arcade Basic Theme:

Warning: Illegal string offset ‘width’ in /home/xxxxxxx/public_html/wp-content/themes/arcade-basic/image.php on line 27

Warning: Illegal string offset ‘height’ in /home/xxxxxx/public_html/wp-content/themes/arcade-basic/image.php on line 27

Looking throught the Internet, we have found other websites showing exactly the same kind of error/message in their attachment pages but we couldn’t find any other refference so as to solve the problem. Could anyone tell us what is this about and if there is any way to solve it??

Thank you very much for your help!