Creating a collage in Picmonkey

[mrshayes]

(Sorry if this is in the wrong place)

I'm not a photographer, but I figured this was the best place to go. I'm trying to make a message board/collage for some friends. I'm pretty good with Picmonkey and I spent hours making this collage, and then when I uploaded it to a website for printing at 16 x 20 size, it said that the picture quality wasn't good enough.

I set the size to 1500 x 1200 (the internet told me that's the pixel size of a 16x20 image), before I started doing editing.
To make the collage, I went into paint and made a blank white background image. Then, with Picmonkey, I turned it into the various parts of the collage (see link: http://i1192.photobucket.com/albums/aa325/armywife-intraining/collagelayoutlarge.jpg ) . So, for the little image that says "The Teasley Family", I uploaded the white .jpg file I'd created in paint; added a black overlay; then the green overlay on top of that; then the text on top of that. I then merged the layers to fix them into place, and saved it. I did the same for the notepad, although I had to add the grey lines - but not the little sprig image - in paint (it was the last thing I did). The calendar was the same: paint image of just plain white, created a calendar in Picmonkey.

Then in Picmonkey, I took the original plain white image, and resized it to 1500 x 1200 (the size the internet told me will make a 16 x 20 image). Then I took the various elements of the collage, saved as .jpg files on my computer, and arranged/layered them on top to make what you see there.

But then when I went to print using an online photo printing website, it told me that the image quality was too poor. What did I do wrong? Was the size wrong? Was it anything to do with using Paint (remember, I only used Paint to create the original plain white image, and to put in the grey lines)? How can I make it good enough quality to print at 16x20? It has to be that big, because of the calendar.

 

[KmH]

Moved to Graphics Programs and photo Gallery.

1500 x 1200 is the pixel dimensions (resolution) of the image.

For printing, another number comes into play - the pixels per inch or ppi.

At 100 ppi, a 1500 x 1200 image will print as a 15" x 12" print. (1500 pixels / 100 ppi = 15 inches)
To print 1500 pixels at 20 inches - 1500 / 20 inches = 75 pixels-per-inch.
Many online printing services have a minimum ppi requirement, and that minimum is usually 100 ppi - which is partly why I chose it.

To determine the pixels dimensions you need to make a 20 x 16 print at 100 ppi
20 inches x 100 ppi = 2000 pixels
16 inches x 100 ppi = 1600 pixels

100 ppi is about the minimum ppi that will deliver a quality wall size print, like a 16x20. 200 ppi often makes a better looking print, which would require 4000 pixels x 3200 pixels.

The template you linked to has space for 2, 4x6 images (8x12, or 16 x 24).
4x6 is a 3:2 aspect ratio 6 / 4 = 1.4 and 3 / 2 = 1.5), which is quite a bit more rectangular than a closer to square 5:4 aspect ratio image.