I am not sure if I got you right, but I give it a try! You could create a SpriteFont and replace some letters with images - have a look on the .capx! I replaced "Z" with an image and wrote "ZUTTON" to create the String! I erased small letters and numbers from the spritefont - you could use all the numbers to put images instead of them, for example! Or use the small letters, or make different SpriteFonts!
I used blackhornets - SpriteFontGenerator_v2 from this forum to create a spritefont. I opened the spritefont with paint.net and replaced the "Z" with the image! For every "Z" you write with this spritefont the image appear!
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