Inkscape is a great OpenSource vector graphics software running under different OS platforms (Windows, Mac OS, GNU/Linux). You can start using parts of images in a vectorized format. SVG is the preferred Open format.

With the OpenSource text processing system LaTeX you can use PGF and TikZ, but it is far more complex to learn than Inkscape.

See https://inkscape.org/ and https://en.wikipedia.org/wiki/Scalable_Vector_Graphics

You can find a lot of opensource starting SVG biological images using following keywords in a search : wikimedia SVG biology

Have you tried Google Slides?

No, I didn't !

But I think there is some specific software 

montage image sofware essentially photoshop

Any vector graphics software would do the 'trick'. The 'problem' will be that eg. the cell types are quite some work to design and won't be available off-the-shelf.

Thank you all =D 

Inkscape is a great OpenSource vector graphics software running under different OS platforms (Windows, Mac OS, GNU/Linux). You can start using parts of images in a vectorized format. SVG is the preferred Open format.

With the OpenSource text processing system LaTeX you can use PGF and TikZ, but it is far more complex to learn than Inkscape.

See https://inkscape.org/ and https://en.wikipedia.org/wiki/Scalable_Vector_Graphics

You can find a lot of opensource starting SVG biological images using following keywords in a search : wikimedia SVG biology

Dear Didier, thank you so much.