And look at the result in the Preview pane, which is below the one in which you're typing. Tht is what your post will look like when it's on the forum.

Then please follow the manual, take the cell from the notebook, paste it into the post mark it and use the "Code Sample" button:

Clear[normImage, formatImage]
normImage[ext_String, d__ (* path dirs *)] := 
 formatImage[FileNameJoin[{d}], ext] /; StringLength[ext] > 0
formatImage[d_String, ext_String, big_Integer: 1076] := 
 Module[{fN, p, pxy, ims, oo = 0},
   If[! DirectoryQ[d],
    Print[d, " is not a directory here. Bye."];
    Return[$Failed]
    ];
   SetDirectory[d];
   Print["Directory set to \"", d, "\""];
   fN = FileNames[StringJoin["*.", ext]];
   If[ Length[fN] < 1,
    Print["No files *.", ext, " found in directory ", d];
    Return[$Failed]
    ];
   For[o = 1, o <= Length[fN], ++o,
    p = Import[fN[[o]], ext];
    If[ImageQ[p],
     pxy = Import[fN[[o]], "ImageSize"];
     (* die groessere Dimension des Bildes wird auf big gesetzt, 
     die kleinere Dimentsion wird maßstabsgetreu angepaßt. *)
     ims = If[pxy[[1]] > pxy[[2]],
       {big, pxy[[2]] big/pxy[[1]]}, (* else *)
       {pxy[[1]] big/pxy[[2]], big}
       ];
     Export[fN[[o]], p, ImageSize -> ims];
     oo++;
     Print["Done: ", fN[[o]]], (* else *)
     Print["File ", fN[[o]], " does not represent a picture."]
     ]
    ];
   Print[" Done ", oo, " from ", Length[fN], " pictures given."]
   ] /; Positive[big] && StringLength[ext] > 0

Do the same with the theta

In[1]:= \[Theta] + \[Theta]
Out[1]= 2 \[Theta]

this is the official appearance of Theta in Mathematica, nothing wrong with it despite it does not look like a Theta.

There is the possibilty to insert LaTeX symbols, a LaTeX phrase starts and ends with a dollar sign and you can anything type LaTeX allows for. For example the name Mathematica in mathit is $\mathit{Mathematica}$ and a continued fraction is $\begin{equation} x = a_0 + \cfrac{1}{a_1 + \cfrac{1}{a_2 + \cfrac{1}{a_3 + \cfrac{1}{a_4} } } } \end{equation}$ and the Maxwell formula for the velocity of light in vacuum is $\begin{equation}c=\frac{1}{\sqrt{\mu_0\epsilon_0}}\end{equation}$. If you want to see your LaTeX typing in the preview as you type it, start with the beginning and ending dollar sign and type inbetween of the two.