[Plugin: Media library gallery] Default Thumbnails are oversized

Hello guys,

I wish you could send me a light to search or solve this issue.

I’m working with Page
i have added Media Library Gallery Plugin, but when i attach images in page, displaying of every image are too big for the order it for default have, may anyone tell me how can i handle this?.

And another question, how can i replace the bottom information, i was wondering if i can show there a Description of the image.

Best Regards.