Edit photo for credit card use

I'm struggling with adjusting a photo to put on my credit card. The photo was taken from a digital camera and sent to me via email. I am editing in IPhoto but even though I am cropping and making the photo a 'custom size' I am not meeting the criteria for the card company which is:

Image files must:

• Use .jpeg, .jpg, .gif, .png, .tiff, or .bmp file formats
• Be less than or equal to 10 megabytes (that is, 10MB or 10,000 KB).
• Have pixel dimensions that are greater than or equal to 840 x 840.
• Meet the the image guidelines below.

My photo is 'cropped' to 840x840, but the info on the photo says 214x214 22 KB. JPG

Here is the error message that pops up each time I try to download the photo to the credit card website.

The image you selected does not meet our minimum size requirements. Please upload a new image that is at least 840 x 840 pixels, not to exceed 10MB.

What am I overlooking?