On 3 Aug 2020, at 20:41, Offray Vladimir Luna C��rdenas <offray.luna@mutabit.com> wrote:

Hi,

Today I was an introduction to Pharo. As usual, I asked the learner to
taste the environment and syntax by running the examples in excellent
Sven's Elegant Code[1] (BTW, can I translate snips of  it to Spanish?).
When she was adapting the example 6 about converting JPGs to PNGs, we
get the error reported in this mail's subject. I tried running her
example in my machine with her images and with my own and still I got
the same error. What are we missing?

[1] https://medium.com/concerning-pharo/elegant-pharo-code-bb590f0856d0

We are using Pharo 8.x on Manjaro Gnu/Linux 64 bits.

Thanks,

Offray