Hi,
I understand that you are trying to modify the size of the image before appending it to your document.
The height and width property are contained inside the cell array "img.Style". Hence, when you change the alignment after setting the 'height' and 'width', the height and width are again set to the default value. You can instead use the following code for your implementation.
import mlreportgen.report.*
import mlreportgen.dom.*
rpt = Document('test', 'pdf');
open(rpt)
x = [1 2 3 4];
y = [2 4 6 8];
t = tiledlayout(2, 1, 'Padding', 'tight');
t.Units = 'inches';
t.OuterPosition = [0.25 0.25 4 4];
nexttile;
scatter(x, y);
nexttile;
scatter(log(x), log(y))
set(gcf, 'Units', 'inches', 'Position', [0.25 0.25 4 4])
exportgraphics(t, 'test.jpg','Resolution',300);
img = Image('test.jpg');
img.Style = {Height('4in'),HAlign("center"),Width('4in')};
append(rpt, img);
close(rpt);
