diff --git a/nifti2/nifti_tool.c b/nifti2/nifti_tool.c
index ac249bf8..f964d099 100644
--- a/nifti2/nifti_tool.c
+++ b/nifti2/nifti_tool.c
@@ -2843,7 +2843,7 @@ int act_diff_nims( nt_opts * opts )
    if( ! nim0 ) return 1;  /* errors have been printed */
 
    nim1 = nt_image_read(opts, opts->infiles.list[1], 0, 0);
-   if( ! nim1 ){ free(nim0); return 1; }
+   if( ! nim1 ){ nifti_image_free(nim0); return 1; }
 
    if( g_debug > 1 )
       fprintf(stderr,"\n-d nifti_image diffs between '%s' and '%s'...\n",
@@ -3359,6 +3359,7 @@ int act_mod_hdrs( nt_opts * opts )
          if( !nim ) {
             fprintf(stderr,"** failed to dup file '%s' before modifying\n",
                     fname);
+            free(nhdr);
             return 1;
          }
 
@@ -3369,6 +3370,7 @@ int act_mod_hdrs( nt_opts * opts )
          {
             NTL_FERR(func,"failed to set prefix for new file: ",opts->prefix);
             nifti_image_free(nim);
+            free(nhdr);
             return 1;
          }
          dupname = nifti_strdup(nim->fname);  /* so we know to free it */
@@ -3377,6 +3379,8 @@ int act_mod_hdrs( nt_opts * opts )
          if( nifti_image_write_status(nim) ) {
             fprintf(stderr,"** failed to write image %s\n", nim->fname);
             nifti_image_free(nim);
+            free(dupname);
+            free(nhdr);
             return 1;
          }
 
@@ -3477,6 +3481,7 @@ int act_mod_hdr2s( nt_opts * opts )
          if( !nim ) {
             fprintf(stderr,"** failed to dup file '%s' before modifying\n",
                     fname);
+            free(nhdr);
             return 1;
          }
          if( opts->keep_hist && nifti_add_extension(nim, opts->command,
@@ -3486,6 +3491,7 @@ int act_mod_hdr2s( nt_opts * opts )
          {
             NTL_FERR(func,"failed to set prefix for new file: ",opts->prefix);
             nifti_image_free(nim);
+            free(nhdr);
             return 1;
          }
          dupname = nifti_strdup(nim->fname);  /* so we know to free it */
@@ -3494,6 +3500,8 @@ int act_mod_hdr2s( nt_opts * opts )
          if( nifti_image_write_status(nim) ) {
             fprintf(stderr,"** failed to write image %s\n", nim->fname);
             nifti_image_free(nim);
+            free(dupname);
+            free(nhdr);
             return 1;
          }
 
@@ -3623,6 +3631,7 @@ int act_swap_hdrs( nt_opts * opts )
          if( !nim ) {
             fprintf(stderr,"** failed to dup file '%s' before modifying\n",
                     fname);
+            free(nhdr);
             return 1;
          }
          if( opts->keep_hist && nifti_add_extension(nim, opts->command,
@@ -3632,6 +3641,7 @@ int act_swap_hdrs( nt_opts * opts )
          {
             NTL_FERR(func,"failed to set prefix for new file: ",opts->prefix);
             nifti_image_free(nim);
+            free(nhdr);
             return 1;
          }
          dupname = nifti_strdup(nim->fname);  /* so we know to free it */
@@ -3640,6 +3650,8 @@ int act_swap_hdrs( nt_opts * opts )
          if( nifti_image_write_status(nim) ) {
             fprintf(stderr,"** failed to write image %s\n", nim->fname);
             nifti_image_free(nim);
+            free(dupname);
+            free(nhdr);
             return 1;
          }
 
diff --git a/niftilib/nifti1_tool.c b/niftilib/nifti1_tool.c
index 15bb165a..5588b9c4 100644
--- a/niftilib/nifti1_tool.c
+++ b/niftilib/nifti1_tool.c
@@ -2277,7 +2277,7 @@ int act_diff_nims( nt_opts * opts )
    if( ! nim0 ) return 1;  /* errors have been printed */
 
    nim1 = nt_image_read(opts, opts->infiles.list[1], 0);
-   if( ! nim1 ){ free(nim0); return 1; }
+   if( ! nim1 ){ nifti_image_free(nim0); return 1; }
 
    if( g_debug > 1 )
       fprintf(stderr,"\n-d nifti_image diffs between '%s' and '%s'...\n",
@@ -2606,6 +2606,7 @@ int act_mod_hdrs( nt_opts * opts )
          if( !nim ) {
             fprintf(stderr,"** failed to dup file '%s' before modifying\n",
                     fname);
+            free(nhdr);
             return 1;
          }
          if( opts->keep_hist && nifti_add_extension(nim, opts->command,
@@ -2615,6 +2616,7 @@ int act_mod_hdrs( nt_opts * opts )
          {
             NTL_FERR(func,"failed to set prefix for new file: ",opts->prefix);
             nifti_image_free(nim);
+            free(nhdr);
             return 1;
          }
          dupname = nifti_strdup(nim->fname);  /* so we know to free it */
@@ -2623,6 +2625,8 @@ int act_mod_hdrs( nt_opts * opts )
          if( nifti_image_write_status(nim) ) {
             fprintf(stderr,"** failed to write image %s\n", nim->fname);
             nifti_image_free(nim);
+            free(dupname);
+            free(nhdr);
             return 1;
          }
 
@@ -2727,6 +2731,7 @@ int act_swap_hdrs( nt_opts * opts )
          if( !nim ) {
             fprintf(stderr,"** failed to dup file '%s' before modifying\n",
                     fname);
+            free(nhdr);
             return 1;
          }
          if( opts->keep_hist && nifti_add_extension(nim, opts->command,
@@ -2736,6 +2741,7 @@ int act_swap_hdrs( nt_opts * opts )
          {
             NTL_FERR(func,"failed to set prefix for new file: ",opts->prefix);
             nifti_image_free(nim);
+            free(nhdr);
             return 1;
          }
          dupname = nifti_strdup(nim->fname);  /* so we know to free it */
@@ -2744,6 +2750,8 @@ int act_swap_hdrs( nt_opts * opts )
          if( nifti_image_write_status(nim) ) {
             fprintf(stderr,"** failed to write image %s\n", nim->fname);
             nifti_image_free(nim);
+            free(dupname);
+            free(nhdr);
             return 1;
          }