Para tentar melhorar a performance da listagem da agenda, fiz um ViewHolder conforme recomendado, porém estou tomando a exception OutOfMemory quando dou um BitmapFactory.decodeFile.
Segue trecho do código do meu adapter:
AlunosAdapter.java
public View getView(int position, View convertView, ViewGroup parent) {
        View view;
        ViewHolder holder;
        if (convertView == null){
            view = LayoutInflater.from(context).inflate(R.layout.list_item, parent, false);
            holder = new ViewHolder(view);
            view.setTag(holder);
        } else {
            view = convertView;
            holder = (ViewHolder) view.getTag();
        }
        Aluno aluno = (Aluno) getItem(position);
        holder.nome.setText(aluno.getNome());
        holder.telefone.setText(aluno.getTelefone());
        if(aluno.getPathFoto() != null) {
            Bitmap bitmap = BitmapFactory.decodeFile(aluno.getPathFoto());
            holder.foto.setImageBitmap(bitmap);
        }
        return view;
    }ViewHolder.java
public class ViewHolder {
    public final TextView nome;
    public final TextView telefone;
    public final ImageView foto;
    public ViewHolder(View view){
        nome = (TextView) view.findViewById(R.id.item_nome);
        telefone = (TextView) view.findViewById(R.id.item_telefone);
        foto = (ImageView) view.findViewById(R.id.item_foto);
    }
}Exception:
java.lang.OutOfMemoryError: Failed to allocate a 64256268 byte allocation with 16777216 free bytes and 25MB until OOM
                      at dalvik.system.VMRuntime.newNonMovableArray(Native Method)
                      at android.graphics.BitmapFactory.nativeDecodeStream(Native Method)
                      at android.graphics.BitmapFactory.decodeStreamInternal(BitmapFactory.java:635)
                      at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:611)
                      at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:391)
                      at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:417)
                      at com.example.luizpacinni.agenda.adapter.AlunosAdapter.getView(AlunosAdapter.java:63)