Perhaps you need to upsize a photo to let’s say: 48mb.
The simplest and easiest way to upsize is to read my blog and get the Photoshop plug-in you need. You can get a fully functional trial for 1 month. You can get to my blog by CLICKING HERE
BUT. If you simply cannot afford to do that, try this.
1.Shoot in RAW.
2.In your processor transfer to Photoshop direct as a TIFF.
3.Upsize in 5% increments using bicubic smoother.
4.Each 3rd upsize use bicubic sharpener.
5.End the process and change to 8 bit and then JPEG.
You are ready.