It’s not needed right now, i agree. Before going to graphics full moddable engine may be prepared.
By the way, i had a throught that scaling of PNG images is good to be suported as option.
Something like
"images" :
{
// Group of this image. Optional, default = 0
"group" : 0,
// Imdex of the image in group
"frame" : 0,
// Filename for this frame
"file" : "filename.png",
"scaleX": 50, //percents - 100% if not set
"scaleY": 50 //percents - 100% if not set
}.
...
]