I have a problem with the following fie :
\useexternalfigure[fig1][Mouette1]%1600x1200
\useexternalfigure[fig2][Mouette2]%1024x768

\starttext
%the following line gives an error :
%Error: pdfetex.exe (file ./Mouette1.jpg): reading JPEG image failed
%\externalfigure[fig1]

%the following lines runs very well 
\page
\externalfigure[fig2]
\stoptext

Is there a limitation of the dimensions of a picture ?
Or another problem ?
Thank you