[web] Optimized images on benchmarks part 2.

...eat-transport-bhe/3D_BHE_GW_advection_figures/rel_err.png

...e/3D_BHE_GW_advection_figures/temperature_soil_2years.png

...at-transport-bhe/3D_Beier_sandbox_figures/Inflow_temp.png

...dbox_figures/comparison_with_experiment_data_and_OGS5.png

...he/3D_Beier_sandbox_figures/numerical_geometry_of_BHE.png

...ort-bhe/3D_Beier_sandbox_figures/soil_temp_comparison.png

...port-bhe/3D_coaxial_deep_BHE_figures/coaxial_deep_BHE.png

.../3D_coaxial_deep_BHE_figures/numerical_geometry_model.png

...p_BHE_figures/outflow_temperature_over_time_long-term.png

...axial_deep_BHE_figures/temperature_distribution_3000s.png

...transport-bhe/pipe_flow_EBHE_figures/T_out_comparison.png

...bhe/pipe_flow_EBHE_figures/absolute_error_fluid_T_30d.png

...ansport-bhe/pipe_flow_EBHE_figures/pipe_flow_3d_model.png

...s/heatconduction/BHE_array_benchmark_figures/figure_1.png

...s/heatconduction/BHE_array_benchmark_figures/figure_2.png

...s/heatconduction/BHE_array_benchmark_figures/figure_3.png

...s/heatconduction/BHE_array_benchmark_figures/figure_4.png

...s/heatconduction/BHE_array_benchmark_figures/figure_5.png

...nd_simulated_temperature_line_source_term_in_cylinder.png

...nd_simulated_temperature_line_source_term_in_cylinder.png