Quiet@Remove["Global`*"];
$HistoryLength=2;
SetDirectory[NotebookDirectory[]];

{data25,data45,data85,data105}=<<"struct";

model=a+b*(Exp[c*u]-1);
resfit=FindFit[data105,model,{a,b,c},u]
Plot[model/.resfit,{u,0,0.3}];

ClearAll[zprac]
zprac[{data_,hue_}]:=Module[{model, resfit,a,b,c,pl1a,pl1b,umin,umax,imin,imax,pl2},
model=a+b*(Exp[c*u]-1);
resfit=FindFit[data,model,{a,b,c},u,Method->NMinimize];
{umin,umax}={Min[#],Max[#]}&[(First/@data)];
{imin,imax}={Min[#],Max[#]}&[(Last/@data)];
pl1a=Plot[model/.resfit,{u,umin,umax},PlotStyle->{Thickness[0.005],Hue[hue]},AxesLabel->{"u [V]","i [A]"},GridLines->{Range[0,1.1umax,((umax-umin)/20)],Range[0,1.1imax,((imax-umin)/20)]},PlotLabel->"i= "<>ToString[TraditionalForm[model/.resfit]],PlotRange->All];
pl1b=Plot[model/.resfit,{u,umin,umax},PlotStyle->{Thickness[0.005],Hue[hue]},AxesLabel->{"u [V]","i [A]"},GridLines->{Range[0,1.1umax,((umax-umin)/20)],Range[0,1.1imax,((imax-umin)/20)]},PlotRange->All];
pl2=ListPlot[data,PlotStyle->{PointSize[0.01],Hue[hue*1.05]},PlotRange->All];
{Show[pl1a,pl2],Show[pl1b,pl2]}
]
zprac[{data105,0.7}];

vys=zprac/@Thread[{{data25,data45,data85,data105},{0.1,0.3,0.4,0.6}}];

graf=Show[Last/@vys,PlotRange->All]

Export["vys.png",graf,ImageResolution->300]

f[i_]:=Export["vys"<>ToString[i]<>".png",(First/@vys)[[i]],ImageResolution->300]
f/@Range[4]