The die is the image. The package is how that die is presented to a PCB: pinout, height, thermal path, cover glass, and whether you can even place it. Two shop rows can share a part number family and still be different packages. That is why "the same IMX335" is not a specification.
In one sentence. Package is the mechanical and electrical costume of the die. Modules add another costume on top. Compare the stack, not the nickname.
What changes when the package changes
- Height and keep-out. A CSP and a PLCC do not fit the same can.
- Cover glass and IR properties. Some packages include a filter. Some do not.
- CRA and the microlens family, occasionally. Do not assume.
- The module maker's PCB, holder, and firmware. This is where two "IMX335 cameras" stop being cousins.
The older PCB-colour post on this blog is the same lesson from the solder-mask side. The stack leaks into the picture.
How to use the library
On the sensor page, Package is a real filter. Use it when you already have a holder or a flex. If you are designing the module, pick the die first and the package as a layout constraint. If you are buying a finished module, stop comparing only the sensor nickname. Compare the module.