Like many others on this forum I can't see the thumbnail images using Simple Image Gallery Pro on my website, although mine originally were working and have all of a sudden disappeared.  I would really appreciate assistance with this as I haven't altered the plugin parameters at all and have run the 'Fix Permissions' function of Akeeba Admin Tools but to no avail. 

I'm having the exact same issue with mine.
K2 seems to accept the flickr url and generate the images in the tab, no errors when saving the item but when you go to it in the site there is no images, thumbnails or anything. Checking the source shows that no HTML has been generated by the plugin to show the images.
I have reset the permissions with akeeba admin and tried running it with the default joomla template with no success.

Anyone know whats going on here????

Please provide us with a link to your gallery page please.

I have the same problem, i install the last version of k2 and sigpro
I upload a zip gallery in an element and I can see all thumbnails in the backend in element but nothing on frontend at all for this element.
I follow all permissions in documentation for sigpro.
Where can I search for a solution ?
url:http://aeetee.ca/component/k2/item/72-ateliercqjdctrefie
However, I continue to search for a solution and I cannot leave this element in that state. I now delete the zip file attached to it.
See the image joined for what happens when I want to open that element.
Thank you.

I cannot see the plugin in your page. Did you remove it?

Yes and I had already write it in the first question, I cannot leave these article without the photos. So I put all the photos in a table in the element.
How can I help you to help me?

I have reset the permissions with akeeba admin and tried running it

@corde, please pm me access to your backend so as to test the plugin in another article if possible.