It may just be something you can solve with layering. Have her try to place the images "behind" the text. Most text wont have backgrounds and youll be able to see through the letters to the background images. Also, if you didn't design these without a background in photoshop even a PNG can have a white background so, a few questions:
Are you illustrating these digitally?
If No, there is little that can be done about the white around traditional art, short of creating complicated clipping paths and masking the white in post editing (photoshop)unless you mess with the layer properties in the final layout software (more about this below).
If Yes then make sure you dont have a white background on your end. Keep the art (lines and colors) on a separate layer than the "background". Come time to export from photoshop turn off the background layer and export your png. check the "transarency" box and make sure you see the grid in the preview like this:
0_1537463796058_Screen Shot 2018-09-20 at 1.16.01 PM.png
Is she designing them on a light colored or textured background?
If yes, try setting the layer to some sort of transparency in the final design software similar to photoshops "multiply". It'll make the white basically blend in with the the background and not block out big chunks of other elements but only slightly alter the color of your art, like this (pardon the typos):
0_1537463498564_Screen Shot 2018-09-20 at 1.11.00 PM.png
OK. If none of that works and push comes to shove...drop the jpg into powerpoint, "set transparent color", select the white then right click+save as the image from ppt with the background removed and, voila. PNG with transparent background:
"set transparent color"
0_1537464248357_Screen Shot 2018-09-20 at 1.21.47 PM.png
Right click+Save as
0_1537464291970_Screen Shot 2018-09-20 at 1.21.57 PM.png
Hope that all helps!!
(Im a graphic designer by trade, layouts and working with files is a lot of what i do :))