You can import svg-s into blender.
Svg is 2D, and for anything to show up after the import in blender you need to make paths inside the svg. Then the paths will be used as curves in blender.

Further on, a raster image/photograph won't work by definition.
First you would need to trace it over/use trace bitmap.

Then if you got that imported to blender, it won't be 3D by a sudden.
You will need to extrude it at least and for an obj you need to export it.
(Still that would be far from a model of a T-shirt that could look similar to one on a torso.)

Svg is sort of a container document. If you have an embedded raster image only, it won't show up.
Make it plain simple, for importing.


Oh well, even if things are working, you might not notice it, right?
In blender after importing, change to wireframe rendering mode (Z) and check on the outliner on the right - the svg will be imported as objects named curve, curve.001, and so on.
Select the desired object there.
In the properties editor on the right -at the curve setting's tab- the object's id-s are displayed that were used in inkscape.

Now if you check the 3D viewport window's right side tab, the dimensions are displayed.
Keep an eye to them: blender uses 1 m as a default unit -so if your svg was within page borders, it would be smaller than x: 0.21, y: 0.297.


Maybe you can share your file if you get really stuck.