More resizing help

[Frog]

A friend has asked me if I could resize some pics for him. He and his wife travel the country selling at festivals, fairs, etc.
Some of the shows are juried selection and they need some pics resized to meet requirements.
After reading GB1 question and responses on upping resolution I had tried a few of my own with good results. Up-res?

My friends may be just too small to do though. The dimensions are 855 pixels by 833 pixels or 11.875 inches by 11.569 inches and the resolution is 72 inches per inch.
The jury requirements are that the image be 1 MB size and/or formatted to Zapplication requirements. I don't know what that is.

Should I start with the resolution....if I go straight to 300 pixels per inch it blurs the whole photo...or start with the 855 pixels or go with the pixels per inch increasing in 10% increments?
Sample pic with their business name removed.

Ok......I've gone back and upped the resolution per inch in small(10%) increments and it comes out pretty good.
Anything else I should be aware of? Oh...going to 300 pixels per inch upped it to over 3MB.

[another view]

I had never heard of Zapplication but there's a ton to read about it here.

They want square format images, but I'm not sure if yours is close enough. If you try to more than double the size of it to 1920 x 1920 (quadruple it, actually), it will be blurry. Is there a higher resolution original file available?

I would think they only need this for possible printing of promo material. On screen, your image looks great.

[Frog]

I had some time to fool with it last night and by upping the resolution to 300 pixels per inch in gradual 10% increments it ends up fine. Only problem is it made it 3 MB so now I'm going back to see what happens when I reduce it.
That zapplication thing looks great for artists and those that work the shows.

[freygr]

I would put it photoshop or elements and just resize to the the Zapplication spec. 1920 square jpg less than 3 mb file size.