Unable to upload a picture to an image card

Hi Support Team,

I'm trying to use the image card to include some screen shots, However, when I browse and upload the image file, it didn't get shown up. Attached is the screen shot for the image card after I have uploaded the image.

Further more, is there any restriction of the image file type (i.e. jpg, png, ...)? And also any restriction on the image size that allowed to be uploaded?

Hope to hear from you soon.

Thanks.

regards,

Evonne